When the key K is pressed at time t = 0, which of the following statements about the current I in the resistor AB of the given circuit is true?

(1) I = 2 mA at all t

(2) I oscillate between 1 mA and 2mA

(3) I = 1 mA at all t

(4) At t = 0 , I = 2 mA and with time it goes to 1 mA

A torch bulb rated as 4.5 W, 1.5 V is connected as shown in the figure. The e.m.f. of the cell needed to make the bulb glow at full intensity is :

(1) 4.5 V

(2) 1.5 V

(3) 2.67 V

(4) 13.5 V

In the circuit shown in the figure, the current through :

1. The 3Ω resistor is 0.50A

2. The 3Ω resistor is 0.25 A

3. The 4Ω resistor is 0.50A

4. The 4Ω resistor is 0.25 A

There are three resistance coils of equal resistance. The maximum number of resistances you can obtain by connecting them in any manner you choose, being free to use any number of the coils in any way is :

(1) 3

(2) 4

(3) 6

(4) 5

If in the circuit shown below, the internal resistance of the battery is 1.5 Ω and V_P and V_Q are the potentials at P and Q respectively, what is the potential difference between the points P and Q 

(1) Zero

(2) 4 volts (V_P > V_Q)

(3) 4 volts (V_Q > V_P)

(4) 2.5 volts (V_Q > V_P)

Two wires of resistance R₁ and R₂ have temperature coefficient of resistance ${\alpha }_1\text{ and }{\alpha }_2$, respectively. These are joined in series. The effective temperature coefficient of resistance is :

(1) $\frac{{\alpha }_1+{\alpha }_2}{2}$

(2) $\sqrt{{\alpha }_1{\alpha }_2}$

(3) $\frac{{\alpha }_1{R}_1+{\alpha }_2{R}_2}{R_1+R_2}$

(4) $\frac{\sqrt{R_1{R}_2{\alpha }_1{\alpha }_2}}{\sqrt{R_1^2+R_2^2}}$

Two cells of equal e.m.f. and of internal resistances, r_1, and $r_2(r_1>r_2)$ are connected in series. On connecting this combination to an external resistance R, it is observed that the potential difference across the first cell becomes zero. The value of R will be :

(1) $r_1+r_2$

(2) $r_1-r_2$

(3) $\frac{r_1+r_2}{2}$

(4) $\frac{r_1-r_2}{2}$

When connected across the terminals of a cell, a voltmeter measures 5V and a connected ammeter measures 10 A of current. A resistance of 2 ohms is connected across the terminals of the cell. The current flowing through this resistance will be :

(1) 2.5 A

(2) 2.0 A

(3) 5.0 A

(4) 7.5 A

In the circuit shown here, E₁ = E₂ = E₃ = 2 V and R₁ = R₂ = 4 ohms. The current flowing between points A and B through battery E₂ is 

(1) Zero

(2) 2 amp from A to B

(3) 2 amp from B to A

(4) None of the above

In the circuit shown below, \(E_1 = 4.0~\text{V}\), \(R_1 = 2~\Omega\), \(E_2 = 6.0~\text{V}\), \(R_2 = 4~\Omega\) and \(R_3 = 2~\Omega\). The current \(I_1\) is:

1. \(1.6\) A

2. \(1.8\) A

3. \(1.25\) A

4. \(1.0\) A