Understanding Electric Potential

Q.

An electrical technician requires a capacitance of 2 µF in a circuit across a potential difference of 1 kV. A large number of 1 µF capacitors are available to him each of which can withstand a potential difference of not more than 400 V. Suggest a possible arrangement that requires the minimum number of capacitors.

Q. A battery of e.m.f E and internal resistance r is connected across a resistance R. The resistance R can be adjusted to any value greater than or equal to zero. A graph is plotted between the current (I) passing through the resistance and potential difference (V) across it. Select the correct alternatives.

1. Internal resistance of the battery is $5\Omega$
2. E.m.f. of the battery is 10 V.
3. Maximum current which can be taken from the battery is 2 A.
4. V – I graph can never be a straight line as shown in the figure.

Q.

Is the terminal voltage greater than EMF?

Q. 64.A circuit given in the figure has section AB , with E=10V, C1=1 if, C2=2uF & the potential difference Va-Vb=5 V.the voltage across C1 is A. 0 B. 5V C. 10V D. 15V

Q.

An LCR series circuit is at resonance with 10v each across L, C & R. If the resistance is halved, the respective voltage across L, C & R are

a) 10v, 10v & 5v. b) 10v, 10v & 10v. c) 20v, 20v & 5v

d) 20v, 20v & 10v

MTG finger tips. Chapter ac . Que.no. 63. Answers.d

Q. In the circuit shown, the current in $3\Omega$ resistance is

1. $1\text{A}$
2. $\frac{1}{7}\text{A}$
3. $\frac{5}{7}\text{A}$
4. $\frac{15}{7}\text{A}$

Q. a 30 v , 90w lamp is to be operated on a 120 v dc lines.for proper glow, how much resistance should be connected in series with the lamp?

Q. The e.m.f. of a cell is ε and its internal resistance is r. Its terminals are connected to a resistance R. The potential difference between the terminals is 1.6 V for $R=4\Omega$ and 1.8 V for $R=9\Omega$. Then,

1. $\epsilon =1V,r=1\Omega$
2. $\epsilon =2V,r=2\Omega$
3. $\epsilon =2.5V,r=0.5\Omega$
4. $\epsilon =2V,r=1\Omega$

Q. In a series LCR AC circuit RMS voltage of L, Cand R are V1, V₂ and V3 respectively then
A. equal toV1+V2+V3
B. Equal to V1-V2+V3
C. More than V1+V2+V3
D. None of these

Q. Express which of the following setups can be used to verify Ohm’s law

1. a
2. b
3. c
4. d

Q. An alternating voltage E=200sin(300t)is applied across a series combination of R is equal to 10 ohm and inductance of 800 Milli Henry calculate impedance of circuit

Q. In the circuit as shown in figure, if all the symbols have their usual meanings, then identify the correct option.

1. $q_2=q_3;V_2=V_3$
2. $q_1=q_2+q_3;V_2=V_3$
3. $q_1=q_2+q_3;V=V_1+V_2+V_3$
4. $q_1+q_2+q_3=0;V_2=V_3=V-V_1$

Q. A 2 $V$ battery is connected across the points A and B as shown in the figure given below. Assuming that the resistance of each diode is zero in forward bias and infinity in reverse bias, the current supplied by the battery when one of the diodes has its positive terminal is connected to $A$ (as shown in figure) is

1. $0.2A$
2. $0.4A$
3. $0$
4. $0.1A$

Q. For the given figure, which battery is doing positive work?

1. $E_1$
2. $E_2$
3. Both $E_1$ and $E_2$
4. None of these

Q. Figure shows part of a circuit . Which points have the same potential as that of point $a$?

1. $c$
2. $i$
3. $f$
4. $g$

Q. 22.6 ohm and 12 ohm resistors are connected in parallel.This combination is connected to series with a 10 V battery and 6ohm resistor. What is the potential difference between the terminals of the 12 ohm resistance?

Q. A battery consists of $n$ number of identical cells having internal resistance connected in series. The terminals of the battery are short circuited and the current $I$ is measured.
Which of the following graphs shows correct relationship between $I$ and $n$?

1. 
2. 
3. 
4. 

Q.
For setup shown in diagram, find $V_A-V_B$

1. 13 V
2. 16 V
3. 8 V
4. 12 V

Q. The equivalent capacitance of the combination shown in figure (31-Q1) is
(a) C
(b) 2 C
(c) C/2
(d) none of these.

Figure

Q. A battery of e.m.f E and internal resistance r is connected across a resistance R. The resistance R can be adjusted to any value greater than or equal to zero. A graph is plotted between the current (I) passing through the resistance and potential difference (V) across it. Select the correct alternatives.

1. Internal resistance of the battery is $5\Omega$
2. E.m.f. of the battery is 10 V.
3. Maximum current which can be taken from the battery is 2 A.
4. V – I graph can never be a straight line as shown in the figure.

Q. Resistances are connected as shown in figure. The potential difference between A & B is:

1. 48 V
2. 64 V
3. 24 V
4. 36 V

Q. Four cells each of emf $1.9V$ and the internal resistance $1\Omega$ are connected to an external resistance of $18Omega$ as shown in the figure. Find the terminal potential difference of this combination.

Q. The figure shows two similar capacitors connected to a battery. Initially, switch was closed and when opened, the capacitors were filled with a dielectric of dielectric constant $3$. The potential difference across capacitor B is:

1. $6V$
2. $3V$
3. $\frac{3}{2}V$
4. $2V$

Q. State whether given statement is True or False
A series circuit acts as a voltage divider.

1. True
2. False

Q. As given in the figure, a series circuit connected across a $200$V $,60$ Hz line consists of a capacitor of capacitive reactance $30\Omega$, a non-inductive resistor of $44\Omega$, and a coil of inductive reactance $90\Omega$ and resistance $36\Omega$. The power dissipated in the coil is

1. 320 W
2. 176 W
3. 144 W
4. 0 W

Q. An electron is accelerated under a potential difference of $182$V. The maximum velocity of electron will be(Charge of electron is $1.6\times {10}^{-19}$C and its mass is $9.1\times {10}^{-31}$kg)

1. $5.65\times {10}^{6}m/s$
2. $4\times {10}^{6}m/s$
3. $16\times {10}^{6}m/s$
4. $8\times {10}^{6}m/s$

Q. A series AC circuit has a resistance of 4 Ω and a reactance of 3 Ω. The impedance of the circuit is

(a) 5 Ω
(b) 7 Ω
(c) 12/7 Ω
(d) 7/12 Ω

Q. A capacitor of $8F$ is connected as shown. Charge on the plates of the capacitor is

1. $40C$
2. $32C$
3. $80C$
4. $0C$

Q. Refer to the figure shown below where the symbols have their usual meanings and select the correct option among the following.

1. $Q_1=Q_2=Q_3$ and $V_1=V_2=V_3=V$
2. $Q_1=Q_2+Q_3$ and $V=V_1+V_2+V_3$
3. $Q_1=Q_2+Q_3$ and $V=V_1+V_2$
4. $Q_2=Q_3$ & $V_2=V_3$

Q. A $5.0\mu F$ capacitor having a charge of $20\mu C$ is discharged through a wire of resistance $5.0\Omega$. Find the heat dissipated in the wire between $25$ to $50\mu s$ after the connections are made. (Given :$e^{-2}=0.135)$.