Current Electricity · Question 70

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

1. 0.5 Ω
2. 1/3 Ω
3. 1/4 Ω
4. 1 Ω

If power dissipated in the 9 Ω resistor in the circuit shown is 36 watt, the potential difference across the 2 Ω resistor is [figure]

1. 4 volt
2. 8 volt
3. 10 volt
4. 2 volt

Consider the following two statements. Which of the following is correct?

1. Both (A) and (B) are wrong
2. (A) is correct and (B) is wrong
3. (A) is wrong and (B) is correct
4. Both (A) and (B) are correct

A potentiometer circuit is set up as shown. The potential gradient, across the potentiometer wire, is k volt/cm and the ammeter, present in the circuit, reads 1.0 A when two way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be at length l1 cm and l2 cm respectively. The magnitudes, of the resistors R and X, in ohms, are then, equal, respectively, to [figure]

1. k(l2 - l1) and kl2
2. kl1 and k(l2 - l1)
3. k(l2 - l1) and kl1
4. kl1 and kl2

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

1. 2 - i2r2 - 1 - i1r1 = 0
2. - 2 - (i1 + i2)R + i2r2 = 0
3. 1 - (i1 + i2)R + i1r1 = 0
4. 1 - (i1 + i2)R - i1r1 = 0

A wire of resistance 12 ohms per metre is bent to form a complete circle of radius 10 cm. The resistance between its two diametrically opposite points, A and B as shown in the figure is [figure]

1. 3
2. 6
3. 6
4. 0.6

A student measures the terminal potential difference (V) of a cell (of emf and internal resistance r) as a function of the current (I) flowing through it. The slope, and intercept, of the graph between V and I, then respectively, equal

1. -r and
2. r and -
3. - and r
4. and -r

The mean free path of electrons in a metal is 4 10-8 m. The electric field which can give on an average 2 eV energy to an electron in the metal will be in units V/m

1. 5 10-11
2. 8 10-11
3. 5 107
4. 8 107

[figure] In the circuit shown, the current through the 4 resistor is 1 amp when the points P and M are connected to a d.c. voltage source. The potential difference between the points M and N is

1. 0.5 volt
2. 3.2 volt
3. 1.5 volt
4. 1.0 volt

A wire of a certain material is stretched slowly by ten percent. Its new resistance and specific resistance become respectively

1. both remain the same
2. 1.1 times, 1.1 times
3. 1.2 times, 1.1 times
4. 1.21 times, same