Physics - Current Electricity - Quiz-11

The potential difference $(V_{B} - V_{A})$ between points A and B in the figure is? if $R = 0.7 Ω$ and i = 3 is

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3 V
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15 V
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5.1 V
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+5.1 V

A set of 'n' equal resistors, of value 'R' each, are connected in series to a battery of emf 'E' and internal resistance 'R'. The current drawn is I. Now, the 'n' resistors are connected in parallel to the same battery. Then the current drawn becomes 10I. The value of 'n' is:

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10
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11
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20
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9

The resistance of a wire is ‘R’ ohm. If it is melted and stretched ‘n’ times its original length, its new resistance will be:-

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$\frac{R}{n}$
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$n^{2} R$
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$\frac{R}{n^{2}}$
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nR

A carbon resistor (47 ± 4.7) kΩ is to be marked with rings of different colours for its identification. The colour code sequence will be:

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Violet - Yellow - Orange - Silver
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Yellow - Violet - Orange - Silver
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Yellow - Green - Violet - Gold
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Green - Orange - Violet - Gold

The figure shows a circuit that contains three identical resistors with resistance R = 9.0 $Ω$ each, two identical inductors with inductance L = 2.0 mH each, and an ideal battery with emf $ε = 18$ V. The current 'i' through the battery just after the switch closed is:

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0.2A
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2A
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4 A
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2mA

The potential difference $V_{A} - V_{B}$ between the points A and B in the given figure is :
The potential difference (VA - VB) between the points A and

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-3V
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+3V
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+6V
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+9V

A filament bulb (500 W, 100 V) is to be used in a 230 V main supply. When a resistance R is connected in series, the bulb works perfectly and consumes 500 W. The value of R is :

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230 $Ω$
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46 $Ω$
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26 $Ω$
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13 $Ω$

The charge flowing through a resistance R varies with time t as Q = at - bt², where a and b are positive constants. The total heat produced in R is:

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$\frac{a^{3} R}{3 b}$
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$\frac{a^{3} R}{2 b}$
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$\frac{a^{3} R}{b}$
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$\frac{a^{3} R}{6 b}$

Two metal wires of identical dimensions are connected in series. If $σ_{1} and σ_{2}$ are the conductivities of the metal wires respectively, the effective conductivity of the combination is:

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$\frac{2 σ_{1} σ_{2}}{σ_{1} + σ_{2}}$
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$\frac{σ_{1} + σ_{2}}{2 σ_{1} σ_{2}}$
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$\frac{σ_{1} + σ_{2}}{σ_{1} σ_{2}}$
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$\frac{σ_{1} σ_{2}}{σ_{1} + σ_{2}}$

A circuit contains an ammeter, a battery of 30 V, and a resistance 40.8 $Ω$ all connected in series. If the ammeter has the coil of resistance 480 $Ω$ and a shunt of 20 $Ω$ , then reading in the ammeter will be:

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0.5 A
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0.02 A
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2 A
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1 A

A, B and C are voltmeters of resistance R, 1.5 R and 3R respectively as shown in the figure. When some potential difference is applied between X and Y, the voltmeter readings are V_A, V_B and V_C respectively.

Then,

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V_A = V_B = V_C
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V_A $\neq$ V_B = V_C
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V_A = V_B $\neq$ V_C
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V_A $\neq$ V_B $\neq$ V_C

Across a metallic conductor of non-uniform cross-section, a constant potential difference is applied. The quantity which remains constant along the conductor is :

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current density
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current
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drift velocity
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electric field

The figure shows a circuit when resistance in the two arms of the meter bridge are 5 and R, respectively. When the resistance R is shunted with an equal resistance, the new balance point is at 1.6 l₁. The resistance 'R' is:

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10
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15
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20
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25

The resistances of the four arms P, Q, R and S in a Wheatstone’s bridge are 10 ohm, 30 ohm, 30 ohm and 90 ohm, respectively. The e.m.f. and internal resistance of the cell are 7 Volt and 5 ohm respectively. If the galvanometer resistance is 50 ohm, the current drawn from the cell will be :

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2. 0.1
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1. 0.2 A
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3. 2.0 A
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4. 1.0 A

If power dissipated in the 9 $Ω$ resistor in the circuit shown is 36 W, the potential difference across the 2 $Ω$ resistor is:

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8 V
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10 V
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2 V
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4 V

A current of 2 A flows through a 2 $Ω$ resistor when connected across a battery. The same battery supplies a current of 0.5 A when connected across a 9 $Ω$ resistor. The internal resistance of the battery is:

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1/3 $Ω$
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1/4 $Ω$
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1 $Ω$
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0.5 $Ω$

The rate of increase of thermo-emf with the temperature at the neutral temperature of a thermocouple:

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is zero.
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depends upon the choice of the two materials of the thermocouple.
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is negative.
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is positive.

See the electrical circuit shown in this figure. Which of the following equations is a correct equation for it?

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$\varepsilon_1-(i_1+i_2)R-i_1r_1=0$
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$\varepsilon_2-i_2r_2-\varepsilon_1-i_1r_1=0$
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$-\varepsilon_2-(i_1+i_2)R+i_2r_2=0$
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$\varepsilon_1-(i_1+i_2)R+i_1r_1=0$

A current of 3 A flows through the 2 Ω resistor shown in the circuit. The power dissipated in the 5 Ω resistor is :

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4 W
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2W
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1 W
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5W

The total power dissipated in watts in the circuit shown here is:

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16 W
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40 W
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54 W
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4 W

Three resistances P, Q, R, each of 2 Ω and an unknown resistance S form the four arms of a Wheatstone bridge circuit. When the resistance of 6 Ω is connected in parallel to S, the bridge gets balanced. What is the value of S?

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2 $Ω$
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3 $Ω$
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6 $Ω$
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1 $Ω$

In the circuit shown, if a conducting wire is connected between points A and B, the current in this wire will: (All resistance given in ohms)

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flow from A to B
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flow in the direction which will be decided by the value of V
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be zero
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flow from B to A

Two cells having the same emf, are connected in series through an external resistance R. Cells have internal resistance r₁ and r₂ respectively. When the circuit is closed, the potential difference across the first cell is zero. The value of R is:

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$r_{1} - r_{2}$
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$\frac{r_{1} + r_{2}}{2}$
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$\frac{r_{1} - r_{2}}{2}$
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$r_{1} + r_{2}$

The power dissipated across the 8 Ω resistor in the circuit shown here is 2 W. The power dissipated in watts across the 3 Ω resistor is:

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2.0
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1.0
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0.5
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3.0

Six similar bulbs are connected as shown in the figure with a DC source of emf E and zero internal resistance.

The ratio of power consumption by the bulbs when (i) all are glowing and (ii) in the situation when two from section A and one from section B are glowing, will be:

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2: 1
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4: 9
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9: 4
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1: 2

An ideal ammeter (zero resistance) and an ideal voltmeter (infinite resistance) are connected as shown in Fig. 6.47. The ammeter and the voltmeter readings are :

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6.25 A, 3.75 V
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3.00 A, 5V
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3.00 A, 3.75 V
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6.00 A, 6.25 V

In the circuit shown in Fig.6.50, an ideal ammeter and an ideal voltmeter are used. When the key is open the voltmeter reads 1.53 V. When the key is closed, the ammeter reads 1.0 A and the voltmeter reads 1.03 V. The resistance R is :

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0.5 $Ω$
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1.03 $Ω$
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1.53 $Ω$
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0.53 $Ω$

Three voltmeters are connected as shown.

A potential difference has been applied between A and B. On closing the switch S, readings of volmeters?

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$V_{1}$ increases
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$V_{1}$ decreases
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$V_{2} a n d V_{3}$ both increase
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One of $V_{2} a n d V_{3}$ increases and other decreases

In the circuit in Fig. 7.27, bulb B does not glow although ammeter A indicates that the current is flowing. Why does the bulb not glow?

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The bulb is fused.
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There is a break in the circuit between bulb and ammeter.
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The variable resistor has too large resistance.
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There is a break in the circuit between the bulb and the variable resistance.

All bulbs in Fig. 7.30 are identical. Which bulb lights more brightly?

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1
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2
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3
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4

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Practice Physics Quiz Questions and Answers

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Practice Physics Quiz Questions and Answers

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