(\(r\gg\) separation of two charges forming the dipole, \(\varepsilon_{0} =\) permittivity of free space)
| 1. | \(\overrightarrow{E}=\dfrac{\overrightarrow{P}}{4\pi \varepsilon _{0}r^{3}}\) | 2. | \(\overrightarrow{E}=\dfrac{2\overrightarrow{P}}{\pi \varepsilon _{0}r^{3}}\) |
| 3. | \(\overrightarrow{E}=-\dfrac{\overrightarrow{P}}{4\pi \varepsilon _{0}r^{2}}\) | 4. | \(\overrightarrow{E}=-\dfrac{\overrightarrow{P}}{4\pi \varepsilon _{0}r^{3}}\) |
A plane-convex lens of unknown material and unknown focal length is given. With the help of a spherometer, we can measure the
| 1. | focal length of the lens. |
| 2. | radius of curvature of the curved surface. |
| 3. | aperture of the lens. |
| 4. | refractive index of the material. |
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 |
The efficiency of a Carnot engine depends upon:
1. the temperature of the sink only.
2. the temperatures of the source and the sink.
3. the volume of the cylinder of the engine.
4. the temperature of the source only.
For the circuit shown in the figure, the current \(I\) will be:
| 1. | \(0.75~\text{A}\) | 2. | \(1~\text{A}\) |
| 3. | \(1.5~\text{A}\) | 4. | \(0.5~\text{A}\) |
Two coherent sources of light interfere and produce fringe patterns on a screen. For the central maximum, the phase difference between the two waves will be:
1. zero
2. \(\pi\)
3. \(\dfrac{3\pi}{2}\)
4. \(\dfrac{\pi}{2}\)
The total energy of an electron in the \(n^{th}\) stationary orbit of the hydrogen atom can be obtained by:
1. \(E_n = \frac{13.6}{n^2}~\text{eV}\)
2. \(E_n = -\frac{13.6}{n^2}~\text{eV}\)
3. \(E_n = \frac{1.36}{n^2}~\text{eV}\)
4. \(E_n = -{13.6}\times{n^2}~\text{eV}\)
| 1. | \(e^{\omega t}\) | 2. | \(\text{log}_e(\omega t)\) |
| 3. | \(\text{sin}\omega t+ \text{cos}\omega t\) | 4. | \(e^{-\omega t}\) |
| 1. | \(102\times10^{-3}~\text{nm}\) | 2. | \(102\times10^{-4}~\text{nm}\) |
| 3. | \(102\times10^{-5}~\text{nm}\) | 4. | \(102\times10^{-2}~\text{nm}\) |
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