Simple Circuit

Q. Each side of regular polygon of $n$ sides has a resistance $R$. The equivalent resistance between any two adjacent vertices is

1. $nR$
2. $\frac{R}{n}$
3. $\frac{(n-1)R}{n}$
4. $\frac{n}{n-1}R$

Q.

A capacitor of capacitance $\mathrm{C}$ is charged to a potential difference $\mathrm{V}$ from a cell and then disconnected from it. A charge $+\mathrm{Q}$ is now given to its positive plate. The potential difference across the capacitor is now _________.

Q.

Two amplifiers are connected one after the other in series (cascaded). The first amplifier has a voltage gain of 10 and the second has a voltage gain of 20. If the input signal is 0.01 volt, calculate the output ac signal.

Q.

Least count of ammeter and voltmeter are?

Q.

Two capacitors of 6 μf and 4 μf are put in series across a 120 V battery. What is the potential difference across the 4 μf capacitor?

1. 60 V

2. 48 V

3. zero

4. 72 V

Q.

In the arrangement of resistances shown below, the effective resistance between points A and B is

1. $20\Omega$

2. $30\Omega$

3. $90\Omega$

4. $110\Omega$

Q. In the circuit shown in the figure, the total charge is $750\mu \text{C}$ and the voltage across capacitor $C_2$ is $20\text{V}$. Then the charge on capacitor $C_2$ is-

1. $450\mu \text{C}$
2. $590\mu \text{C}$
3. $160\mu \text{C}$
4. $650\mu \text{C}$

Q.

Four resistances $ 40 \Omega , 60 \Omega , 90 \Omega $ and $ 110 \Omega $ make the arms of a quadrilateral ABCD. Across AC is a battery of EMF $ 40 V$ and internal resistance negligible. The potential difference across BD in $ V$ is _______.

Q. The magnitude and direction of the current in the circuit shown will be

1. $\frac{7}{3}$ A from a to b through e.
2. $\frac{7}{3}$ A from b to a through e.
3. $1\text{A}$ from b to a through e.
4. $1\text{A}$ from a to b through e.

Q. In $\text{LR}$ circuit, the $\text{AC}$ source has voltage $220\text{V}$. If the potential difference across the inductor is $176\text{V}$, the potential difference across the resistor will be

1. $44\text{V}$
2. $396\text{V}$
3. $132\text{V}$
4. $176\text{V}$

Q. The current in an $L-R$ circuit, in a time $t=\frac{2L}{R}$ reduces to
(Take $e=2.731$)

1. $36.5\%$ of maximum
2. $13.4\%$ of maximum
3. $0.50\%$ of maximum
4. $63.2\%$ of maximum

Q.

In the figure given, the electric current flowing through the$5k\Omega$ resistor is$xmA.$

The value of $x$ to the nearest integer is ________.

Q. In a region of constant potential

1. the electric field is zero
2. there can be no charge inside the region.
3. the electric field is uniform
4. the electric field shall necessarily change if a charge is placed outside the region.

Q. In the given circuit, the potential of the point E is

1. Zero
2. -8V
3. - 4/3 V
4. 4/3 V

Q. A cell of emf $E$ and internal resistance $r$ is connected across a variable resistor $R$. Plot a graph showing variation of terminal voltage $V$ of the cell with the current $I$. Using the plot, show how the emf of the cell and its internal resistance can be determined.

Q. Three light bulbs $(60\text{W},120\text{V})$ are connected across a $120\text{V}$ power source. If the resistance of each bulb does not change with current, then find out total power delivered to the three bulbs.

1. $80\text{W}$
2. $60\text{W}$
3. $40\text{W}$
4. $20\text{W}$

Q. If in the given figure i = 0.25 amp, then the value R will be

1. $48\Omega$
2. $12\Omega$
3. $120\Omega$
4. $42\Omega$

Q. Two identical heater wires are first connected in series and then in parallel with a source of electricity.

The ratio of heat produced in the first case to heat produced in second case is:

1. $4:1$
2. $1:2$
3. $2:1$
4. $1:4$

Q. 12 wires each having resistance r are joined to form a cube as shown.find the equivalent resistance between the ends of a face diagonal such as A and C.find the equivalent resistance between ends of an edge such as A and B and also along body diagonal A amd F

Q. Consider the circuit shown in the figure. The current i₃ is equal to

1. 5 amp
2. 3 amp
3. – 3 amp
4. $-\frac{5}{6}$ amp

Q. Obtain expression for effective emf and internal resistance when two different cell connect parallel

Q.

(a)Three resistors 1 Ω, 2 Ω, and 3 Ω are combined in series. What is the total resistance of the combination?

(b) If the combination is connected to a battery of emf 12V and negligible internal resistance, obtain the potential drop across each resistor.

Q. First, a set of n equal resistor of $10\Omega$ each are connected in series to a battery of emf 20 V and internal resistance $10\Omega$. A current I is observed to flow. Then, the n resistors are connected in parallel to the same battery. It is observed that the current is increased 20 times, then the value of n is

Q. 27. In the given circuit the potential difference across 3uF capacitor will be : (1) 16 V (2) 10 V (3) 6 V (4) 4 V

Q. 35.In the circuit shown below the cell has emf of 10 V and internal resistance of 1 ohm . The other resistances are shown in figure. Calculate the potential difference V(a)-V(b).

Q.

If the cell is short circuited, its terminal potential difference is

1. zero

2. unity

3. infinity

4. none of these

Q. Two coils are at fixed locations. When coil-$1$ has no current and current in the coil-$2$ increases at the rate $15.0{\text{As}}^{-1}.$ The e.m.f. in the coil-$1$ is $25.0\text{mV}$. When coil-$2$ has no current and coil-$1$ has a current of $3.6\text{A}.$, the flux linkage in coil-$2$ is-

1. $16\text{mWb}$
2. $10\text{mWb}$
3. $4\text{mWb}$
4. $6\text{mWb}$

Q. The deflection produced in the galvanometer is reduced to 45 divisions from 55 when a shunt of 8 ohm is used. Calculate the resistance of the galvanometer.

Q. A uniformly wound long solenoid of self inductance $L$ is cut into two parts having lengths in the ratio $1:2$, which are then connected in parallel. The effective inductance of the combination will be -

1. $\frac{2L}{9}$
2. $\frac{L}{9}$
3. $\frac{4L}{9}$
4. $\frac{5L}{9}$

Q.

The potential difference between the terminals of a battery of emf 6.0 V and internal resistance 1 $\Omega$ drops to 5.8 V when connected across an external resistor. Find the resistance of the external resistor.