Current Electricity

The stored charge in the capacitor in steady state of the following circuit is μC. [figure]

Refer to the circuit diagram given below. The heat generated across the 6 resistance in 100 second is 100 J. The value of is . (Nearest integer) [figure]

Two cells of emfs 1 V and 2 V and internal resistance 2 and 1 , respectively connected in parallel, gave a current of 1 A through an external resistance. If the polarity of one cell is reversed, then value of current through the external resistance will be 5 A. The value of is .

Refer to the figure given below. The values of I1, I2 and I3 are . [figure]

1. I1=2.5 A, I2=1.875 A, I3=1.875 A
2. I1=1.875 A, I2=2.5 A, I3=1.875 A
3. I1=1.875 A, I2=1.875 A, I3=2.5 A
4. I1=2.5 A, I2=2.5 A, I3=1.875 A

Refer to the figure given below, current between terminals A and B is A. [figure]

1. 12.5
2. 1.25
3. 7.5
4. 5

Under steady state condition the potential difference across the capacitor in the circuit is V. [figure]

1. 0.5
2. 1.5
3. 0
4. 2

When an external resistance of 5 is connected across terminals of a cell, a current of 0.25 A flows through it. When the 5 resistor is replaced by a 2 resistor, a current of 0.5 A flows through it. The internal resistance of the cell is .

The voltage and the current between A and B points shown in the circuit are . [figure]

1. 24 V, 12 A
2. 24 V, 4 A
3. 18 V, 12 A
4. 27 V, 4 A

Two resistors of 200 Ω and 400 Ω are connected in series with a battery of 100 V. A bulb rated at 200 V, 100 W is connected across the 400 Ω resistance. The potential drop across the bulb is V.

1. 25
2. 50
3. 66.6
4. 100

For the two cells having same EMF E and internal resistance r, the current passing through the external resistor 6 is same when both the cells are connected either in parallel or in series. The value of internal resistance r is .

1. 3
2. 6
3. 4
4. 9

In the potentiometer, when the cell in the secondary circuit is shunted with 4 resistance, the balance is obtained at the length 120 cm of wire. Now when the same cell is shunted with 12 resistance, the balance is shifted to a length of 180 cm. The internal resistance of cell is

1. 4
2. 12
3. 6
4. 3

The equivalent resistance between the points A and B in the following circuit is x5 . The value of x is . [figure]

A Wheatstone bridge is initially at room temperature and all arms of the bridge have same value of resistances (R1 = R2 = R3 = R4). When R3 resistance is heated to some temperature, its resistance value has gone up by 10%. The potential difference (Va - Vb) (after R3 is heated) is V. [figure]

1. 1.05
2. 0.95
3. 0
4. 2

Two resistors of 100 each are connected in series with a 9 V battery. A voltmeter of 400 resistance is connected to measure the voltage drop across one of the resistors. The voltmeter reading is V.

1. 3
2. 2
3. 4
4. 4.5

Two resistors 2 and 3 are connected in the gaps of bridge as shown in figure. The null point is obtained with the contact of jockey at some point on wire XY. When an unknown resistor is connected in parallel with 3 resistor, the null point is shifted by 22.5 cm toward Y. The resistance of unknown resistor is . [figure]

1. 3
2. 1
3. 4
4. 2

The reading of the ammeter (A) in steady state in the following circuit (assuming negligible internal resistance of the ammeter) is A. [figure]

1. 1/2
2. 1
3. 2
4. 0

A regular hexagon is formed by six wires each of resistance r and the corners are joined to the centre by wires of same resistance. If the current enters at one corner and leaves at the opposite corner, the equivalent resistance of the hexagon between the two opposite corners will be

1. 35r
2. 45r
3. 58r
4. 34r

In a meter bridge experiment to determine the value of unknown resistance, first the resistances 2 and 3 are connected in the left and right gaps of the bridge and the null point is obtained at a distance l cm from the left. Now when an unknown resistance x is connected in parallel to 3 resistance, the null point is shifted by 10 cm to the right of wire. The value of unknown resistance x is .

A wire of uniform resistance /m is bent into a circle of radius r and another piece of wire with length 2r is connected between points A and B (AOB) as shown in figure. The equivalent resistance between points A and B is . [figure]

1. ( + 1)2r
2. 6 r3 + 16
3. 3 r8
4. 2 r

A meter bridge with two resistances R1 and R2 as shown in figure was balanced (null point) at 40 cm from the point P. The null point changed to 50 cm from the point P, when 16 resistance is connected in parallel to R2. The values of resistances R1 and R2 are . [figure]

1. R2 = 8 , R1 = 163
2. R2 = 12 , R1 = 123
3. R2 = 4 , R1 = 43
4. R2 = 16 , R1 = 163

An electric power line having total resistance of 2 , delivers 1 kW of power at 250 V. The percentage efficiency of transmission line is .

1. 96.9
2. 92.5
3. 86.5
4. 100

A cylindrical conductor of length 2 m and area of cross-section 0.2 mm2 carries an electric current of 1.6 A when its ends are connected to a 2 V battery. Mobility of electrons in the conductor is 10-3 m2/V s. The value of is : (electron concentration = 5 1028 /m3 and electron charge = 1.6 10-19 C)

The heat generated in 1 minute between points A and B in the given circuit, when a battery of 9 V with internal resistance of 1 is connected across these points is J. [figure]

Two known resistances of R and 2R and one unknown resistance X are connected in a circuit as shown in the figure. If the equivalent resistance between points A and B in the circuit is X , then the value of X is . [figure]

1. 2( 3 - 1)R
2. R
3. ( 3 - 1)R
4. ( 3 + 1)R

The total length of potentiometer wire AB is 50 cm in the arrangement as shown in the figure. If P is the point where the galvanometer shows zero reading then the length AP is cm. [figure]

1. 25
2. 30
3. 15
4. 20

A battery with EMF E and internal resistance r is connected across a resistance R. The power consumption in R will be maximum when:

1. R = 2r
2. R = 2r
3. R = r2
4. R = r

A wire of resistance R is bent into a triangular pyramid as shown in figure with each segment having same length. The resistance between points A and B is R/n. The value of n is : [figure]

1. 16
2. 10
3. 12
4. 14

Current passing through a wire as function of time is given as I(t) = 0.02t + 0.01 A. The charge that will flow through the wire from t = 1 s to t = 2 s is

1. 0.02 C
2. 0.07 C
3. 0.06 C
4. 0.04 C

There are 'n' number of identical electric bulbs, each is designed to draw a power p independently from the mains supply. They are now joined in series across the mains supply. The total power drawn by the combination is :

1. np
2. p
3. pn2
4. pn

From the combination of resistors with resistance values R1 = R2 = R3 = 5 and R4 = 10 , which of the following combination is the best circuit to get an equivalent resistance of 6 ?

1. [figure]
2. [figure]
3. [figure]
4. [figure]