2nd Year Physics Chapter 13 Current Electricity Notes MCQs Solutions

physics 12th notes mcqs chapter 13

1. The charge carriers in metallic conductors are one of the following:  

 
 
 
 

2. Resistivity of a material depends on

 
 
 
 

3. The device, which converts heat energy into electrical energy is called :

 
 
 
 

4. A student has 5 resistances each of value is 1/5 ohm. The minimum
resistance that can be obtained by combining in parallel is

 
 
 
 

5. The resistance on a one metre cube of a conductor is called :

 
 
 
 

6. Charge carriers in electrolytes are:

 
 
 
 

7. Which of the following materials is useful for making standard resistance

 
 
 
 

8. When electric current passes through the conductors, it increases which among the following:

 
 
 
 

9. For an open circuit

 
 
 
 

10. A fuse is placed in series with the line wire of house circuit to protect against

 
 
 
 

11. A piece of wire has a resistance R. Another wire of same length and
material but twice in diameter has resistance

 
 
 
 

12. The resistance of the conductor does not depend upon its :

 
 
 
 

13. The effects of bends in a wire on its electrical resistance are :

 
 
 
 

14. The resistance of a conductor depends upon :

 
 
 
 

15. In order to have a constant current through a wire, the potential difference across its ends should be :

 
 
 
 

16. Resistivity at a given temperature depends upon:

 
 
 
 

17. Find charge flows among the following options:

 
 
 
 

18. The magnitude of charge flowing is,

 
 
 
 

19. The loss of electrical energy per second is called :

 
 
 
 

20. If the resistance of the conductor is increased, the current will :

 
 
 
 

21. A current of I ampere is passing through a conductor, what will be the charge passing through it in one minute is:

 
 
 
 

22. The resistance of the conductor increase with the increase in its :

 
 
 
 

23. If the resistivity of the conductor is large then it is :

 
 
 
 

24. The substances having negative temperature co-efficient are

 
 
 
 

25. The current through a resistor of 100 Ohm when connected across a
source of 220 V

 
 
 
 

26. The condition for wheat stone bridge is

 
 
 
 

27. The temperature coefficient of resistivity α=

 
 
 
 

28. If one end of the fixed terminals and sliding contact of a rheostat are connected in a circuit, it is to be used as :

 
 
 
 

29. The reciprocal of a resistance is called :            

 
 
 
 

30. A voltmeter can read the correct potential difference only when the current drawn by it from the cell is :

 
 
 
 

31. The net charge flowing across the cross-sectional area per unit time will be known as one of the following:

 
 
 
 

32. The graphical representation of Ohm’s law is 

 
 
 
 

33. Resistance tolerance of silver band is

 
 
 
 

34. The SI unit of resistivity is :                     

 
 
 
 

35. Kirchhoff’s first rule is a manifestation of law of enervation of :

 
 
 
 

36. The quantity having the same unit as that of emf is :

 
 
 
 

37. The reciprocal of resistivity is :               

 
 
 
 

38. Ohm is the unit

 
 
 
 

39. The conductors which obey Ohm’s law are called :

 
 
 
 

40. The magnitude of magnetic effects depends upon :

 
 
 
 

41. Ohm is defined as

 
 
 
 

42. The unit of emf is :            

 
 
 
 

43. A battery made a charge of 40 C around a circuit at constant rate in 20 second The current will be

 
 
 
 

44. Electromotive force is closely related to

 
 
 
 

45. Electrolysis is the study of conduction of electricity through :

 
 
 
 

46. The electrode connected with positive terminal of battery is called :

 
 
 
 

47. The electromotive force of a battery or cell is the voltage b/W its terminals when

 
 
 
 

48. Internal resistance is the resistance offered by

 
 
 
 

49. How will you calculate power from current I and Voltage V

 
 
 
 

50. If the resistivity of the conductor is small then it is :

 
 
 
 

51. The thermostats convert of temperature into:

 
 
 
 

52. The SI unit of conductance is :

 
 
 
 

53. Which one is the best conductor :

 
 
 
 

54. The numerical value of black color in carbon resistors is:

 
 
 
 

55. In case of metallic conductors, the charge carriers are

 
 
 
 

56. In the construction of a rheostat, we use manganin which is an alloy of :

 
 
 
 

57. New prepared ceramic material have been found to be super conductor even at :

 
 
 
 

58. The charge per unit time through any cross-section of a conductor is called

 
 
 
 

59. Heat generated by a 40 W bulb in one hour is

 
 
 
 

60. The electrode connected with negative terminal of battery is called :

 
 
 
 

61. One Coulombsec⁻¹ =

 
 
 
 

62. Conversion of chemical energy into electrical energy can be achieved by :

 
 
 
 

63. If the temperature of a’ conductor is increased, the product of resistivity and Conductivity

 
 
 
 

64. A 100 watt bulb is operated by 200 volt, the current flowing through the
bulb is

 
 
 
 

65. ρ =

 
 
 
 

66. The resistance of a conductor does not depend on its

 
 
 
 

67. Heat sensitive resistors are called:

 
 
 
 

68. Thermistors are prepared under :                       

 
 
 
 

69. The resistance of the conductor increases due to rise of temp of a conductor because collision cross-section of the atoms :

 
 
 
 

70. Reciprocal of resistivity of a material is called

 
 
 
 

71. A 1000 watt heater operates on a 220 volt line for one hour. The current passing through the heater is

 
 
 
 

72. A conductor which strictly obeys ohm’s law is called

 
 
 
 

73. In series circuit, the pot difference across each resistance is :

 
 
 
 

74. Kirchhoff’s first law is the manifestation of law of conservation of

 
 
 
 

75. Semi-conductor diode is an example of

 
 
 
 

76. Terminal potential difference is always of battery

 
 
 
 

77. The colour strip on carbon resistor from extreme left are yellow, black and
red its resistance is

 
 
 
 

78. The velocity of an oscillating charge as it moves to and fro along the wire is: 

 
 
 
 

79. The tolerance of silver band is

 
 
 
 

80. The conductance of a conductor increases by

 
 
 
 

81. The resistance of a conductor through which a current Of one ampere is flowing when a potential difference across its ends is one volt is : 

 
 
 
 

82. When ever current is drawn from the battery, its emf and terminal potential difference became :

 
 
 
 

83. The resistance of the conductor increases due to the rise of temperature of
conductor , because the collision cross section of the atoms

 
 
 
 

84. At constant temp, the current flowing through a conductor is directly proportional to the potential difference across its ends will be known as :

 
 
 
 

85. Electromotive force is given by the formula

 
 
 
 

86. During electrolysis process, density of CuS04 solution :

 
 
 
 

87. Electric heater is the effect of electric current :

 
 
 
 

88. R=

 
 
 
 

89. When the current is drawn from a cell, its terminal potential difference and emf are:

 
 
 
 

90. ∆Q=

 
 
 
 

91. The resistance of a meter cube of a material is called its

 
 
 
 

92. An instrument which can measure potential without drawing any current is called

 
 
 
 

93. V=IR represents

 
 
 
 

94. By increasing the temperature of conductor, the flow rate of charge

 
 
 
 

95. Why should different resistances be added in series in a circuit

 
 
 
 

96. When the current is being drawn from the battery :

 
 
 
 

97. Two resistors of 2 ohm & 4 ohm are connected in parallel their equivalent
resistance is

 
 
 
 

98. S.I unit of electromotive force is

 
 
 
 

99. Potentiometer can be used as a

 
 
 
 

100. Electronic current is due to flow of

 
 
 
 

101. The motion of free electrons inside the metallic conductors is one of the following:

 
 
 
 

102. A device which is a wire wound resistance called :

 
 
 
 

103. SI unit of resistivity is

 
 
 
 

104. A carbon resistor consists of_____colour bands

 
 
 
 

105. Three arms of a balanced wheat stone bridge are of 75 ohms resistance of
each. What is the resistance of fourth arm?

 
 
 
 

106. The resistivity of a conductor increases with

 
 
 
 

107. Current flows in the gases due to:

 
 
 
 

108. Thermistors with high negative temperature coefficient are very accurate for measuring low temperature especially near.

 
 
 
 

109. The electronics current is due to the flow of which among the following:

 
 
 
 

110. I=

 
 
 
 

111. To use a rheostat as variable resistor, the terminals which are inserted in a circuit are :

 
 
 
 

112. The graphical representation of Ohm’s law is

 
 
 
 

113. SI unit of conductance is

 
 
 
 

114. In parallel circuit, the current has :

 
 
 
 

115. A wire of uniform area of cross section “A”, length “L” and resistance “R” is
cut into two equal parts. The resistivity of each part

 
 
 
 

116. If there is no fourth band the tolerance is

 
 
 
 

117. Resistance of a substance of one meter in length and one square meter in
cross section is called

 
 
 
 

118. When a battery is being charged, its terminal potential difference is :

 
 
 
 

119. The potential difference between, the head and tail of an electric eel is:

 
 
 
 

120. A complex system consisting of a number of resistors can be solved by

 
 
 
 

121. Chemical effect of current during electrolysis depends on

 
 
 
 

122. The vessel containing the two electrodes and certain liquid is known :

 
 
 
 

123. The charge carriers in electrolyte are

 
 
 
 

124. Terminal potential difference of a battery is greater than its emf when

 
 
 
 

125. Resistance and resistivity of a substance :       

 
 
 
 

126. A wire having very high value of conductance is said to be :

 
 
 
 

127. Thermo-couple convert into electrical energy choose one.

 
 
 
 

128. Wheatstone bridge consists of—–resistances

 
 
 
 

129. The tolerance of gold band is

 
 
 
 

130. Non-ohmic devices are :

 
 
 
 

131. Which is the Most practical applications of electricity:

 
 
 
 

132. Tolerance for silver band is:

 
 
 
 

133. Thermistors are made from mixtures of metallic oxides of :

 
 
 
 

134. When the temperature of a conductor is raised, its resistance :

 
 
 
 

135. The wire used in the construction of a rheostat is of the material :

 
 
 
 

136. P=

 
 
 
 

137. If the resistance in three successive arms of balanced bridge is 1,2 and 36
ohms respectively , the resistance in the fourth arm will be

 
 
 
 

138. Conductance is :   

 
 
 
 

139. Which one of the following bulb has least resistance

 
 
 
 

140. Kirchhoff’s second rule is a manifestation of law of conservation of :

 
 
 
 

141. I=

 
 
 
 

142. If the source of emf traversed from positive to negative terminals, the potential change are:

 
 
 
 

143. If the source of emf is traversed from negative to positive terminal, what will be the potential change :

 
 
 
 

144. The study of conductance of Electricity through liquids is known as :

 
 
 
 

145. If 1 ampere current flows through 2m long conductor, the charge flow
through this conductor in 1 hour will be

 
 
 
 

146. If both fixed as well as the sliding contact of a rheostat are connected in a circuit, it is to be used as :

 
 
 
 

147. The magnitude of the drift velocity is of the order of :

 
 
 
 

148. A rheostat can be used as variable resistor as well as a

 
 
 
 

149. The resistance of a 60 watt bulb in a 120 volt line is

 
 
 
 

150. Through metallic conductor the current is because of flow of

 
 
 
 

151. The current which flow from a point at higher potential to a point at lower potential is called

 
 
 
 

152. The conductors which do not obey Ohm’s law are called :

 
 
 
 

153. Drift velocity is used when the ends of a wire are:

 
 
 
 

154. Three resistances 5000, 500 and 50 Ohms are connected in series across
555 volts main. The current flowing through them will be

 
 
 
 

155. For Ohmic device the graph between V and I is

 
 
 
 

156. The voltameter usually contains :                       

 
 
 
 

157. An electric current in a wire involves the movement of which among the following:

 
 
 
 

158. When the Wheatstone bridge is balanced, the galvanometer shows zero deflection because :

 
 
 
 

159. 1 kilo watt hour is equal to

 
 
 
 

160. For non-ohmic devices, the graph between V and I is :

 
 
 
 

161. Reciprocal of resistance is called

 
 
 
 

162. If a 40 watt light bulb burns for 2 hours how much heat is generated

 
 
 
 

163. Color codes are used to calculate the:

 
 
 
 

164. The apparatus used to compare the emf of two cells is

 
 
 
 

165. The wire of resistance R is cut into two equal parts, the resistance of each part becomes R/2, what happens to resistivity.

 
 
 
 

166. The minimum resistance that can be obtained by combining them in Parallel is:

 
 
 
 

167. The minimum resistance that can be obtained by combining 50 resistance each 0f ¼
ohm is

 
 
 
 

168. When two spherical conducting balls at different potentials are joined by metallic wire, after some time, potential difference will be :

 
 
 
 

169. The resistivity of decrease with the increase in temp.

 
 
 
 

170. Which of the following is used to determine the internal resistance of a cell

 
 
 
 

171. A post office box is an apparatus whose construction is based on the principle of a

 
 
 
 

172. Magnetic effect of current is used :

 
 
 
 

173. By electromotive force

 
 
 
 

174. In Carbon resistors, the value of Blue color is:

 
 
 
 

175. When the temperature of a conductor is increased its resistance

 
 
 
 

176. Specific resistance of material depends upon:

 
 
 
 

177. The value of the resistivity is the least for :                   

 
 
 
 

178. If the resistance of a conductor is increased then current

 
 
 
 

179. A complex system consisting of a many resistances can be solved by :

 
 
 
 

180. Rheostat can be used as a

 
 
 
 

181. Batteries convert

 
 
 
 

182. Wheat stone bridge is an arrangement consisting of :

 
 
 
 

183. The substance having negative temperature co-efficient is:

 
 
 
 

184. The SI unit of the temp coefficient of resistivity of a material is :

 
 
 
 

185. What will be the SI unit of electric current :

 
 
 
 

186. Thermo couple converts heat energy into

 
 
 
 

187. The Fractional change in resistivity per unit original resistivity per Kelvin in temperature is known as :

 
 
 
 

188. Electrical energy is given by the formula

 
 
 
 

189. A heat sensitive resistor is called :                     

 
 
 
 

190. SI unit of temperature coefficient of resistivity is

 
 
 
 

191. Heating effect of current is used in :

 
 
 
 

192. A balanced Wheatstone bridge is used to determine

 
 
 
 

193. Resistance of a conductor increases with increase in

 
 
 
 

194. The potential difference across each resistance in series combination is

 
 
 
 

195. The third band of the colour code :                    

 
 
 
 

196. By increasing the thickness of a wire , its resistance will

 
 
 
 

197. Which of the following metal has the lowest value of temperature
coefficient of resistivity

 
 
 
 

198. The fourth band is a :

 
 
 
 

199. If the resistor is traversed in the direction of current, the potential change are :

 
 
 
 

200. Ampere second stands for the unit of:

 
 
 
 

201. Drift velocity of electrons is

 
 
 
 

202. Algebraic sum of currents meeting at a point is zero according to : 

 
 
 
 

203. Thermistor is a

 
 
 
 

204. One Ohm is equal to:

 
 
 
 

205. The conventional current is due to the flow of which among following:         

 
 
 
 

206. Thermistors may be in the form of :                   

 
 
 
 

207. An electric field is generated along the wire when :

 
 
 
 

208. Maximum power out put of a battery is Pmax=

 
 
 
 

209. The resistance present between the two electrodes of the cell is due to:

 
 
 
 

210. When a wire of length I and resistance R is cut into two equal parts then resistance of each part becomes 

 
 
 
 

211. When same current passes for same time through a thick and thin wire :

 
 
 
 

212. Three resistors of resistance 2, 3 and 6 Ohms are connected in parallel then their equivalent resistance is :

 
 
 
 

213. Electrical energy is measured in

 
 
 
 

214. The average velocity gained by electrons in a conductor placed in electric field is called:

 
 
 
 

215. The conventional current is the name given to current due to flow of :

 
 
 
 

216. Colour code carbon resistance consist of :

 
 
 
 

217. In liquids and gases, the current is due to the motion of:

 
 
 
 

218. S.I unit of electric current is

 
 
 
 

219. For electroplating we use

 
 
 
 

220. The SI unit of resistance is :                    

 
 
 
 

Short Questions

1. A potential difference is applied across the ends of a copper wire.What is the effect on the drift velocity of free electrons by i) increasing the potential difference. ii) Decreasing the length and the temperature of the wire.
2. A voltmeter cannot read the exact emf of a cell.Why?
3. An ordinary bulb is marked 60 watt 200 volt what is its resistance?
4. Can you describe some substances whose resistance decreases with increase in temperature?
5. Define ampere ?
6. Define electric current ?
7. Define electrical power write down its three equations for the power dissipation in a resistor?
8. Define electrical power?
9. Define electromotive force (emf) ?
10. Define resistivity ?
11. Define terminal potential difference?
12. Describe a circuit which will give a continuously varying potential?
13. Describe the chemical effect of current ?
14. Describe the heating effect of current ?
15. Describe the magnetic effect of current ?
16. Describe the principle of potentiometer ?
17. Describe the uses of heating effect and Magnetic effect?
18. Describe the various types of sources of current?
19. Difference between emf Terminal P.D?
20. Discuss briefly the heating and magnetic effects of current?
21. Do bends in wire affect its electrical resistance?
22. Explain flow of current through electrolyte?
23. Explain limitations of ohm’s law ?
24. Explain the principle of wheatstone bridge ?
25. Explain the term Tolerance resistor?
26. Explain why the terminal potential of a battery decreases when the current drawn from it is increased?
27. Find the heat dissipated through a bulb of 100 w in an hour?
28. Give some examples of flow of current in which Ohm’s law in not valid?
29. If the positive and negative connections to the terminals of an automobile battery were revered would you expect the automobile light to function?
30. Is it possible to have a situation in which the terminal voltage will be greater than the emf of the battery?
31. Is the principle of energy conservation always applicable to electrical circuits?
32. State Kirchhoff’s rules?
33. State Kirchhoff’s first rule ?
34. State Kirchhoff’s second rule ?
35. State Ohm’s law.Express it mathematically?
36. Ten resistors of different values are connected in parallel.If the potential drop across one of them is 5 volts what is the potential drop across the remaining nine resistors?
37. Three resistance each having the value of 3 are connected in series find their equivalent resistance ?
38. Verify that in series resistor the equivalent resistance is always larger than largest resistance in series 3 and for parallel resistors the equivalent resistance is always smaller than the smallest resistance in the combination?
39. What are the charge carriers in gases ?
40. What are the charge carries in electrolyte?
41. What are the difficulties in testing whether the filament of a lighted bulb obeys Ohm’s law?
42. What are the SI units of power?
43. What are thermistors?What is their importance or use?
44. What do you mean by conventional current?
45. What do you mean by electroplating ?
46. What do you mean by electroplating?
47. What do you understand by ohmic and non-ohmic substances?
48. What do you understand by resistivity?
49. What is a substrate ?
50. What is a thermistor ?
51. What is a thermocouple ?
52. What is an anode ?
53. What is an avometer?
54. What is an internal resistance ?
55. What is an ohmic substance ?
56. What is cathode ?
57. What is conductance ?
58. What is conductivity?
59. What is electric current?
60. What is electrode ?
61. What is electrolysis ?
62. What is electrolyte ?
63. What is non-ohmic substance ?
64. What is potentiometer?
65. What is potentiometer?Describe its principle?
66. What is resistance ?
67. What is short circuit and open circuit mean to you?
68. What is slide wire bridge?Why are the lengths of the wire taken instead of its resistance while determining unknown resistance?
69. What is the acceleration of moving electrons under the effect of electric filed E ?
70. What is the difference between conventional current and electronic current?
71. What is the graph of an ohmic substance ?
72. What is the graph of ohm’s law ?
73. What is the heat ‘H’ produced by current ‘l’ in the wire of resistance ‘R’ in time ‘t’ ?
74. What is the resistivity of copper?
75. What is the resistivity of gold?
76. What is the resistivity of iron ?
77. What is the resistivity of silver ?
78. What is the resistivity of tungsten ?
79. What is the SI unit of conductance ?
80. What is the SI unit of conductivity?
81. What is the SI unit of current ?
82. What is the SI unit of emf?
83. What is the SI unit of resistance and define it?
84. What is the Si unit of resistivity ?
85. What is the SI unit of resistivity or specific resistance ?
86. What is the value of temperature coefficient of resistance of aluminium ?
87. What is the value of temperature coefficient of resistance of copper?
88. What is the value of temperature coefficient of resistance of silver ?
89. What is the value of temperature coefficient of resistance of tungsten ?
90. What is thermistor?Describe its main uses?
91. What is voltameter ?
92. What is wheatstone bridge?
93. What materials are used for making common resistors?
94. When a Wheatstone bridge is balanced then no current flows through the galvanometer why?
95. When the resistors are said to be connected in series?
96. Which kind of energy do cells convert into ?
97. Which kind of energy do solar cells convert into ?
98. Which law is observed by the Kirchhoff’s second rule ?
99. Why a thin region of a light bulb filament has more possibility to burn than the thicker one?
100. Why does the resistance of a conductor rise with temperature?
101. Why is an alkali cell said to be less efficient than an acid cell ?
102. Why is heat produced in a conductor due to flow of electric current?
103. Why is it dangerous to touch a live wire while standing on earth bare – footed?
104. Why resistance of a conductor is inversely proportional to the area of cross- section of a conductor?
105. Why should the potentiometer wire be long and uniform in diameter?
106. Why some of the electrons are free in conductors?
107. Why the current flows in conductor is not due to the flow of positive changes?
108. Why the resistance of a wire is directly proportional to its length?
109. Why the switch is always placed in series with the live wire in house circuits and not in series with the neutral wire?
110. Why we prefer potentiometer in place of voltmeter for measuring potential difference?
111. Write down some used of thermistors ?
112. Write down three relations for the power dissipation in resistor ?

Long Questions

1. Define electric current and conventional current.
2. Describe the current through a metallic conductor.
3. What are the effects of current?
4. State and explain Ohm’s law. Also define ohmic and non-ohmic substances.
5. Define resistivity and explain the dependence of resistance upon temperature.
6. What are the colour code for carbon resistances?
“7. What is Rheostat? Also describe rheostat as:
(i) Variable resistor (ii) Potential divider”
8. Describe electrical power and power dissipation in resistors.
9. Define electromotive force and terminal potential difference. Also describe its relation.
10. Calculate the maximum power output.
11. State and explain Kirchhoff’s first rule.
12. State and explain Kirchhoff’s second rule.
13. What is Wheatstone Bridge? Describe its construction and working.
14. Describe potentiometer with its uses.
15. How many electrons pass through an electric bulb in one minute if the 300 mA current is passing through it?
16. A charge of 90 C passes through a wire in 1 hour and 15 minutes. What is the current in the wire?
17. Find the equivalent resistance of this circuit, total current drawn from the source and the current through each resistor.
18. A rectangular bar of iron is 2cm by 2cm in cross section and 40cm long. Calculate its resistance if the resistivity of iron is 11 x 10⁻⁸ ohm-meter.
19. The resistance of an iron wire at 0 degree is 1 x 10 ⁴ ohm. What is the resistance at 500 degree if the temperature coefficient of resistance of iron is 5.2 x 10⁻³ per kelvin?

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