 # Multiple choice questions on EMF and Electric measurements(Electric Circuits)

## Multiple Choice Questions

Question 1
For accurate measurements, the resistance of a voltmeter should be
1. infinite
2. as small as possible
3. as large a possible
4. equal to the resistance across which potential difference is to be measured

## Paragraph Type Questions

(A)Use figure given below for questions 2 to 4
Consider the circuit given below Question 2
The rate at which energy is dissipated is 20Ω resistor
(a) 14.2 Watt
(b) 8.97 Watt
(c) 97.7 Watt
(d) 47.2 Watt
Question 3
Current through 10Ω resistor is
1. 1.54 A
2. 0.67 A
3. 1.22 A
4. 2.21 A
Question 4
Power of battery having emf E1=20V is
1. 44.2 Watt
2. 30.8 Watt
3. 13.4 Watt
4. 20 Watt

## Multiple Choice Questions

Question 5
Consider the figure given below If ammeter shows a reading of 10A and voltmeter having internal resistance 3000 Ω measures a voltage of 200V, the resistance R is given by
1. 201.3 Ω
2. 2013 Ω
3. 20.13 Ω
4. 20.00 Ω

Question 6
A constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed is doubled if
(a) both length and radius of wire are halved
(b) both length and radius of wire are doubled
(c) the radius of wire id doubled
(d) length of wire is doubled

Question 7
If a wire of resistance 2Ω is covered with ice and a voltage of 210V is applied across the wire , then rate of melting ice would be
1. 0.85g/s
2. 1.92g/s
3. 6.56g/s
4. none of the above

Question 8
Which of the following statements is/are correct?
1. Both Peltier and Joule effects are reversible
2. Both Peltier and Joule effects are irreversible
3. Joule effect is reversible and Peltier effect is irreversible
4. Joule effect is irreversible and Peltier effect is reversible

Question 9
The arrangement shown below is of the meter bridge experiment. Here AC=x corresponds to the null deflection in the galvanometer. What will be the value of AC if the radius of the wire AB is doubled? 1. x/2
2. x/4
3. 2x
4. x

## Assertion Reason type questions

1. Both assertion and reason are true and reason is correct explanation of assertion
2. Both assertion and reason are true and reason is not the correct explanation of assertion
3. Assertion is true but reason is false
4. Both assertion and reason are false.

Question 10
Assertion
The distribution of currents within the network for a given amount of current always takes place in a way that leads to minimum total power distribution in the circuit
Reason
For maximum output current by a source the source resistance must be equal to external load resistance.

Question 11
Assertion
When temperature of a cold junction of a thermocouple is lowered , the value of neutral temperature of this thermocouple rises
Reason
More thermo emf is produced when temperature difference between two junctions of thermocouple is raised.

Question 12
Assertion
A domestic appliance, working on a three pin , will continue working even if the top pin is removed
Reason
Third pin is used as a safety device.

Question 13
Assertion
A potentiometer of larger length is used for accurate measurements
Reason
Potential gradient for potentiometer of larger length with a given battery becomes small.

## Multiple Choice Questions

Question 14
12 wires each of resistance RΩ are connected in the form of a skeleton cube as shown below in the figure If current I enter at point A and leaves at diagonally opposite point G then the equivalent resistance of the cube would be
(a)12R/5
(b)12R
(c) 6R/5
(d) 5R/6

(B) Consider the figure given below Here AB is a wire of total resistance R0 . A jockey connected at point C can divide the wire into resistors of resistance pR0 and (p-1)R0 . Assuming that the batteries are identical and have zero internal resistance
Question 15
Current through ideal ammeter for any 0<p<1 is Question 16
Value of p for which ammeter reads maximum value is
(a) 0
(b) 1
(c) 2
(d) 3

(C) Consider the circuit given below Question 17
Total resistance in the circuit is
(a) 5Ω
(b) 6Ω
(c) (11/6)Ω
(d) 3Ω

Question 18
Current in the circuit is
(a) 4A
(b) 12A
(c) 6A
(d) 2A

Question 19
Potential difference between points A and E is
(a) 12V
(b) 6V
(c) 10V
(d) 5V

Question 20
Potential at point E is
(a) 10 V above the ground
(b) 10 V below the ground
(c) 2 V above the ground
(d) 2 V below the ground

Question 21
Power supplied by the battery is
(a) 12 W
(b) 10W
(c)22W
(d)24W

## Matrix match type question

Question 22
Consider the two circuits given below Column A Column B (P) Point of lowest potential in circuit A has its value equal to (U) 0.15 A (Q) Circuit current in circuit B is (V) 4V (R) Circuit current in circuit A is (W) 15V (S) Potential of point B in circuit B is (X) 90V (T) Potential at point B in circuit A is (Y) .5A

## Multiple Choice Questions

Question 23
In the circuit shown below the reading of ammeter is the same when both switches open as both switches close. The value of resistance R is
(a) 800Ω
(b) 900Ω
(c) 1200Ω
(d) 1000Ω

(D) For questions from 24 to 26 consider the statement given below
A 20µF capacitor which is initially uncharged is connected to a 6V battery through a resistor with resistance equal to 200Ω
Question 24
Magnitude of final charge q0 on the capacitor is Question 25
How long would it take for capacitor to be charged to (1/2)q0  after it is connected to the battery
(a) 3.8×10-3s
(b) 2.8×10-3s
(c) 2.8×10-4s
(d) 3.8×10-4s
Question 26
The time taken by the capacitor to be charged to 0.80q0 is ## Matrix match type question

Question 27
In the figure given below the circuit contains four capacitors having same capacitance of 10µF and a battery providing a voltage of 90V Match the columns given below

 Column A Column B (P) When switch S2 is open and S1 is closed and then opened after C1 , C2 and C3 are fully charged. Electric potential difference across each capacitor is (W) 0 V (Q) Now after opening S1 if switch S2 is closed, the electric potential difference across each capacitor is (X) V1=V3=36V , V2=V4=18V (R) In another case if switch S1 is open and switch S2 is first closed then electric potential difference across each capacitor is (Y) V=30 V (S) Now if switch S1 is closed , the potential difference across each capacitor is (z) V1=V3=30V , V2=V4=15V

## Multiple Choice Questions

Question 28
Kirchhoff's junction rule is a reflection of
(a) conservation of current density vector.
(b) conservation of charge.
(c) the fact that the momentum with which a charged particle approaches a junction is unchanged (as a vector) as the charged particle leaves the junction.
(d) the fact that there is no accumulation of charges at a junction