| Assertion (A): | When the voltage across the capacitor reaches 50% of its maximum value, the rate of heat dissipation in the resistor falls to \(\frac14\) of its initial value. |
| Reason (R): | The voltage across the capacitor is proportional to the charge on its plates, while the rate of flow of charge is the current (i). This current (i) falls exponentially with a time constant T, and it falls to 50% of its initial value when the capacitor is 50% charged. The rate of heat dissipation, being proportional to i2, falls to \(\frac14\) of its initial value. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | (A) is false but (R) is true. |
The value of resistance for the colour code of the given resistor is:
1. \((36\pm36)~k\Omega~\)
2. \((470\pm47)~k\Omega~\)
3. \((360\pm36)~k\Omega~\)
4. \((360\pm18)~k\Omega~\)
A 4 μF capacitor and a resistance of 2.5 MΩ are in series with a 12 V battery. The time after which the potential difference across the capacitor is 3 times the potential difference across the resistor is: [Given ln(2)= 0.693]
1. 13.86 s
2. 6.93 s
3. 7 s
4. 14 s
The colour code of resistance is given below:
The values of resistance and tolerance, respectively are:
1. 47 k, 10%
2. 4.7 k, 5%
3. 470 , 5%
4. 470 k, 5%
In the figure, a carbon resistor has bands of different colours on its body as shown. The value of the resistance is:
1. 2.2 k
2. 3.3 k
3. 5.6 k
4. 9.1 k
(a) The current in each of the two discharging circuits is zero at t = 0.
(b) The currents in the two discharging circuits at t = 0 are equal but not zero.
(c) The currents in the two discharging circuits at t = 0 are unequal.
(d) C1 loses 50% of its initial charge sooner than C2 loses 50% of its initial charge
Choose the correct option
1. (a) only
2. (b), (d)
3. (c), (d)
4. (a), (d)
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:
1. Violet - Yellow - Orange - Silver
2. Yellow - Violet - Orange - Silver
3. Yellow - Green - Violet - Gold
4. Green - Orange - Violet - Gold
A light bulb, a capacitor and a battery are connected together as shown below with the switch S initially open. When the switch S is closed, which one of the following is true?
1. The bulb will light up for an instant when
the capacitor starts charging.
2. The bulb will light up when
the capacitor is fully charged.
3. The bulb will not light up at all.
4. The bulb will light up and go off at regular intervals.
Consider a capacitor-charging circuit. Let Q1 be the charge given to the capacitor in a time interval of 10 ms and Q2 be the charge given in the next time interval of 10 ms. Let 10 µC charge be deposited in a time interval J, and the next 10 µC charge is deposited in the next time interval t2
1. Q1 > Q2 , t1 > t2
2. Q1 > Q2 , t1 < t2
3. Q1 < Q2 , t1 > t2
4. Q1 < Q2 , t1 < t2
A capacitor of 4 is connected as shown in the circuit. The internal resistance of the battery is 0.5 . The amount of charge on the capacitor plates will be:
1. 0
2. 4
3. 16
4. 8