CBSE Class 12 Physics Current Electricity MCQs Set 03

Question. The efficiency of kettle A is   
(a) 63.34%
(b) 83.34%
(c) 93.34%
(d) 73.34%

Answer: B

Question. Efficiency of kettle B is     
(a) 82.5%
(b) 72.5%
(c) 92.5%
(d) 62.5%

Answer: D

Question. Statement 1: An electric bulb is first connected to a dc source and then to an ac source having the same brightness in both cases.       
Statement 2: The peak value of voltage for an A.C. source is √2 times the root mean square voltage.
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If Statement 1 is false but Statement 2 is true.

Answer: D

Question. Statement 1: Current is passed through a metallic wire, heating it red. When cold water is poured on half of its portion, then the rest of the half portion becomes hotter.
Statement 2: Resistances decrease due to a decrease in temperature and so current through wire increases.               
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: A

Question. Statement 1: Through the same current flows through the line wires and the filament of the bulb but the heat produced in the filament is much higher than that in line wires.
Statement 2: The filament of bulbs is made of a material of high resistance and a high melting point.   
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: A

Statement I: The wire of a potentiometer should be of uniform area of cross section.
Statement II: It satisfies the requirement of the principle of a potentiometer.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false. (e) If Statement I is false but Statement II is true.

Answer: A

Statement I: The higher the range, the greater is the resistance of an ammeter.
Statement II: To increase the range of an ammeter, additional shunt is needed to be used across it.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: D

Question. Just after closing the switch           
(a) 2 mA
(b) 3 mA
(c) 0 mA
(d) None of the above

Answer: C

Question. Long time after the switch is closed       
(a) 2 mA
(b) 3 mA
(c) 6 mA
(d) None of the above

Answer: A

Statement I: The resistance of an ideal voltmeter should be infinite.
Statement II: Lower resistance of voltmeters gives a reading lower than the actual potential difference across the terminals.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: A

Statement I: Voltmeter always gives e.m.f. of a cell if it is connected across the terminals of a cell.
Statement II: Terminal potential of a cell is given by V = E - ir.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: D

Question. Statement 1: A domestic electrical appliance, working on a three-pin will continue working even if the top pin is removed.
Statement 2: The third pin is used only as a safety device.   
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: A

Question. Statement 1: The presence of water molecules makes separation of ions easier in an electrolyte.                   
Statement 2: The presence of water molecules in electrolyte decreases the resistance of electrolyte.
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: B

Question. The value of EMF 𝐸1is 
(a) 8 V
(b) 6 V
(c) 4 V
(d) 2 V

Answer: C

Question. The resistance 𝑅1 has value   
(a) 10 ohm
(b) 20 ohm
(c) 30 ohm
(d) 40 ohm

Answer: A

Statement I: The wires supplying current to an electric heater are not heated appreciably.
Statement II: Resistance of connecting wires is very small and H ∝ R.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: A

Statement I: If the current of a lamp increases by 20%, the percentage increase in the illumination of the lamp is 40%.
Statement II: Illumination of the lamp is directly proportional to the square of the current through the lamp
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: A

Question. Statement 1: Electric appliances with a metallic body; e.g. heaters, presses, etc, have three-pin connections, whereas an electric bulb has a two pin connection.
Statement 2: Three-pin connections reduce the heating of connecting cables.     
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: C

Question. The relation between 𝑅𝐴and the actual value of R is   
(a) R > 𝑅𝐴
(b) R < 𝑅𝐴
(c) R = 𝑅𝐴
(d) Dependent on E and r

Answer: B

Question. The relation between 𝑅𝐵 and the actual value of R is
(a) R < 𝑅𝐵
(b) R > 𝑅𝐵
(c) R = 𝑅𝐵
(d) Dependent upon E and r R is nearly 10 ohm ) is         

Answer: B

Question. Efficiency of a battery when delivering maximum power is   
(a) 100 %
(b) 50 %
(c) 90 %
(d) 40 %

Answer: D

Question. The charge in capacitor C1 is       
(a) 20 μC
(b) 30 μC
(c) 40 μC
(d) 10 μC

Answer: D

Statement 1: Thee.m.f. of the driver cell in the potentiometer experiment should be greater than the e.m.f. of the cell to be determined.
Statement II: The fall of potential across the potentiometer wire should not be less than the e.m.f. of the cell to be determined
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: A

Statement I: In a metre bridge experiment, a high resistance is always connected in series with a galvanometer.
Statement II: As resistance increases, current through the circuit increases.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: B

Statement 1: Heater wire must have high resistance than connecting wires and high metallic point.
Statement II: If resistance is high, the electrical conductivity will be less.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: A

Question. If the resistance of the ammeter is 2 ohm, then the resistance of the voltmeter is:- 
(a) 1 ohm
(b) 2 ohm
(c) 3 ohm
(d) 4 ohm

Answer: C

Question. If the resistance of ammeter is 2 ohm ,then resistance of the resistor which is added in parallel to the voltmeter is   
(a) ⅗ ohm
(b) 2/7 ohm
(c) 3/7 ohm
(d) None of the above

Answer: A

Question. The ratio of 𝑅1/𝑅2 is 

Answer: D

Question. The ratio of 𝑅2/𝑅3 is   

Answer: C

Question. The current that passes through the resistance R2 nearest to the V0 is 

Answer: B

Question. The maximum power rating of a 20.0 ohm fuse wire is 2.0 kW,then this fuse wire can be connected safely to a DC source (negligible internal resistance of   
(a) 300 volt
(b) 190 volt
(c) 250 volt
(d) 220 volt

Answer: B

Question. The charge in capacitor C2 is   
(a) 30 μC
(b) 10 μC
(c) 20 μC
(d) 40 μC

Answer: C

Question. The charge on capacitor C3 is   
(a) 10 μC
(b) 30 μC
(c) 20 μC
(d) 40 μC

Answer: B

Statement I: Since all the current coming to our house returns to powerhouse (as current travels in a closed loop), there is no need to pay the electricity bill.
Statement II: The electricity bill is paid for the power used, not for the current used.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: D

Statement I: Internal resistance of a battery is drawn parallel to a battery in electrical circuit.
Statement II: Heat generated in a battery is due to internal resistance.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.         
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: D

Question. Statement 1: The possibility of an electric bulb fusing is higher at the time of switching ON and OFF   
Statement 2: Inductive effects produce a surge at the time of switch ON and OFF
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: A

Question. Statement 1: The 200 W bulbs glow with more brightness than 100 W bulbs.     
Statement 2: A 100 W bulb has more resistance than a 200 W bulb.
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: A

Question. Just after reopening the switch   
(a) 2 mA
(b) 3 mA
(c) 6 mA
(d) None of the above

Answer: A

Question. Two fuse wires of same potential material are having length ratio 1:2 and ratio 4:1 Then respective ratio of their current rating will be   
(a) 8:1
(b) 2:1
(c) 1:8
(d) 4:1

Answer: A

Question. Find the voltmeter reading after the connection of the resistance.     
(a)  1 V
(b) 2 V
(c) 3 V
(d) 4 V

Answer: B

Question. Ratio of efficiency consumed charges for one time boiling of tea in kettle A to that in kettle B   
(a) 3:5
(b) 2:3
(c) 3:4
(d) 1:1

Answer: C

Question. If the resistance of the coil in kettle A and B is Ra and Rb then we can say     
(a) Ra>Rb
(b) Ra=Rb
(c) Ra<Rb
(d) Data insufficient

Answer: B

Question. If both the kettles are joined with the same source in series one after another then boiling starts in kettle A and kettle B after 
(a) 4 times of their original time
(b) Equal to their original time
(c) 2 times of their original time
(d) Data insufficient

Answer: A

Question. Equivalent resistance of the speakers is   
(a) 12 ohm
(b) 7/3 ohm
(c) 8/3 ohm
(d) 0.375 ohm

Answer: C

Question. Statement 1: Fuse wire must have high resistance and low melting point.     
Statement 2: Fuse is used for small current flow only.
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: C

Question. Statement 1: Two electric bulbs of 50 and 100 W are given. When connected in series 50 W bulb glows more but when connected parallel 100 W bulb glows more.
Statement 2: In series combination, power is directly proportional to the resistance of the circuit. But in parallel combination, power is inversely proportional to the resistance of the circuit.   
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: A

Question. Statement 1: Two bulbs of same wattage, one having a carbon filament and the other having a metallic filament are connected in series. Metallic bulbs will glow more brightly than a carbon filament bulb.
Statement 2: Carbon is a semiconductor.   
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: D

Question. The total current supplied by music system 
(a) 2.25 A
(b) 1 A
(c) 16 A
(d) 1.5 A

Answer: A

Question. The power dissipated in the 4 ohm resistance is     
(a) 9 W
(b) 4.5 W
(c) 13.5 W
(d) 0

Answer: A

Question. The resistance 𝑅2 has value 
(a) 10 ohm
(b) 20 ohm
(c) 30 ohm
(d) 40 ohm

Answer: A

Question. Statement 1: In practical application, the power rating of resistance is not important.   
Statement 2: Property of resistance remain the same even at high temperature.
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: D

Question. Statement 1: Leclanche cell is used, when a constant supply of electric current is not required.
Statement 2: The e.m.f. of a Leclanche cell falls, if it is used continuously.
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: A

Statement I: A potentiometer is preferred over a voltmeter for the measurement of e.m.f. of a cell.
Statement II: A potentiometer is preferred, as it does not draw any current from the cell.
(a) If both Statement I and Statement II are true and the statement II is the correct explanation of the statement I.
(b) If both Statement I and Statement II are true but statement II is not the correct explanation of the statement I.
(c) If Statement I is true but Statement II is false.
(d) If the Statement I and Statement II both are false.

Answer: A

Question. Statement 1: In the given circuit if lamp B or C fuses then the light emitted by lamp A decreases.
Statement 2: Voltage on A decreases.
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: A

Question. Statement 1: If three identical bulbs are connected in series as shown in figure then on closing the switches. Bulb C short-circuited and hence illumination of bulbs A and B decreases.     
Statement 2: Voltage on A and B decreases
(a) If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
(b) If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
(c) If Statement 1 is true but Statement 2 is false.
(d) If the Statement 1 and Statement 2 both are false.

Answer: D