| 1. | \(102\times10^{-3}~\text{nm}\) | 2. | \(102\times10^{-4}~\text{nm}\) |
| 3. | \(102\times10^{-5}~\text{nm}\) | 4. | \(102\times10^{-2}~\text{nm}\) |
Two solid conductors are made up of the same material and have the same length and the same resistance. One of them has a circular cross-section of area \( 𝐴 _1\) and the other one has a square cross-section of area \(A_2.\) The ratio of \(𝐴 _1 / 𝐴 _2 \) is:
1. \(1.5\)
2. \(1\)
3. \(0.8\)
4. \(2\)
If the critical angle for total internal reflection from a medium to vacuum is \(45^{\circ}\), the velocity of light in the medium is:
| 1. | \(1.5\times10^{8}~\text{m/s}\) | 2. | \(\dfrac{3}{\sqrt{2}}\times10^{8}~\text{m/s}\) |
| 3. | \(\sqrt{2}\times10^{8}~\text{m/s}\) | 4. | \(3\times10^{8}~\text{m/s}\) |
A barometer is constructed using a liquid (density = \(760~\text{kg/m}^3\)). What would be the height of the liquid column, when a mercury barometer reads \(76~\text{cm}?\)
(the density of mercury = \(13600~\text{kg/m}^3\))
| 1. | \(1.36~\text m\) | 2. | \(13.6~\text m\) |
| 3. | \(136~\text m\) | 4. | \(0.76~\text m\) |
The acceleration of an electron due to the mutual attraction between the electron and a proton when they are \(1.6~\mathring{A}\) apart is:
\(\left(\dfrac{1}{4 \pi \varepsilon_0}=9 \times 10^9~ \text{Nm}^2 \text{C}^{-2}\right)\)
1. \( 10^{24} ~\text{m/s}^2\)
2. \( 10^{23} ~\text{m/s}^2\)
3. \( 10^{22}~\text{m/s}^2\)
4. \( 10^{25} ~\text{m/s}^2\)
1. \(2.91 \times 10^{-4}~\text{rad} \)
2. \(4.85 \times 10^{-4}~\text{rad} \)
3. \(4.80 \times 10^{-6} ~\text{rad} \)
4. \(1.75 \times 10^{-2}~\text{rad} \)
A light bulb and an inductor coil are connected to an AC source through a key as shown in the figure below. The key is closed and after some time an iron rod is inserted into the interior of the inductor. The glow of the light bulb:
| 1. | decreases | 2. | remains unchanged |
| 3. | will fluctuate | 4. | increases |
An infinitely long straight conductor carries a current of \(5~\text{A}\) as shown. An electron is moving with a speed of \(10^5~\text{m/s}\) parallel to the conductor. The perpendicular distance between the electron and the conductor is \(20~\text{cm}\) at an instant. Calculate the magnitude of the force experienced by the electron at that instant.
1. \(4\pi\times 10^{-20}~\text{N}\)
2. \(8\times 10^{-20}~\text{N}\)
3. \(4\times 10^{-20}~\text{N}\)
4. \(8\pi\times 10^{-20}~\text{N}\)
| 1. | \( \dfrac{{IL}^2}{4} ~\text{A}\text-\text{m}^2 \) | 2. | \( \dfrac{{I} \times \pi {L}^2}{4} ~\text{A}\text-\text{m}^2 \) |
| 3. | \( \dfrac{2 {IL}^2}{\pi}~\text{A}\text-\text{m}^2 \) | 4. | \( \dfrac{{IL}^2}{4 \pi}~\text{A}\text-\text{m}^2 \) |
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