In a p–n junction photocell, the value of the photo electromotive force produced by monochromatic light is proportional to:
| 1. | the intensity of the light falling on the cell. |
| 2. | the frequency of the light falling on the cell. |
| 3. | the voltage applied at the p–n junction. |
| 4. | the barrier voltage at the p–n junction. |
| 1. | uses Einstein's photoelectric equation. |
| 2. | predicts continuous emission spectra for atoms. |
| 3. | predicts the same emission spectra for all types of atoms. |
| 4. | assumes that the angular momentum of electrons is quantized. |
The output of the OR gate is \(1\):
| 1. | if either or both inputs are \(1.\) |
| 2. | only if both inputs are \(1.\) |
| 3. | if either input is zero |
| 4. | if both inputs are zero |
| 1. | \(q\cdot E\) and \(p\cdot E \) |
| 2. | zero and minimum |
| 3. | \(q\cdot E\) and maximum |
| 4. | \(2q\cdot E\) and minimum |
A coil of \(40\) H inductance is connected in series with a resistance of \(8~\Omega\) and the combination is joined to the terminals of a \(2~\text{V}\) battery. The time constant of the circuit is:
1. \(1/5~\text{s}\)
2. \(40~\text{s}\)
3. \(20~\text{s}\)
4. \(5~\text{s}\)
One mole of an ideal gas at an initial temperature of \(T\) K does \(6R\) joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is \(5/3\), the final temperature of the gas will be:
1. \((T-2.4)\) K
2. \((T+4)\) K
3. \((T-4)\) K
4. \((T+2.4)\) K
A battery is charged at a potential of \(15\) V for \(8\) hours when the current flowing is \(10\) A. The battery on discharge supplies a current of \(5\) A for \(15\) hours. The mean terminal voltage during discharges is \(14\) V. The "Watt hour" efficiency of the battery is:
1. \(80\%\)
2. \(90\%\)
3. \(87.5\%\)
4. \(82.5\%\)
Five equal resistances each of resistance \(R\) are connected as shown in the figure below. A battery of \(V\) volts is connected between \(A\) and \(B\). The current flowing in \(AFCEB \) will be:
1. \(\dfrac{V}{R}\)
2. \(\dfrac{V}{2R}\)
3. \(\dfrac{2V}{R}\)
4. \(\dfrac{3V}{R}\)
A galvanometer of \(50~\Omega\) resistance has \(25\) divisions. A current of \(4\times 10^{-4}~\text{A}\) gives a deflection of one division. To convert this galvanometer into a voltmeter having a range of \(25~\text{V}\), it should be connected with a resistance of:
| 1. | \(245~\Omega\) as a shunt |
| 2. | \(2550~\Omega\) in series |
| 3. | \(2450~\Omega\) in series |
| 4. | \(2500~\Omega\) as a shunt |
A \(6\)-volt battery is connected to the terminals of a three-metre-long wire of uniform thickness and resistance of \(100\) ohms. The difference of potential between two points on the wire separated by a distance of \(50\) cm will be:
1. \(3\) V
2. \(1\) V
3. \(1.5\) V
4. \(2\) V
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