- A$\frac{1}{\text{r}}$
- B$\frac{1}{\text{r}^2}$
- C$\text{r}$
- D$\text{r}^2$
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Assertion : Microwave propagation is better than the sky wave propagation.
Reason : Microwaves have frequencies 100 to 300 GHz, which have very good directional properties.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
A horizontal rod of mass 10 gm and length 10 cm is placed on a smooth plane inclined at an angle of 60° with the horizontal, with the length of the rod parallel to the edge of the inclined plane. A uniform magnetic field of induction B is applied vertically downwards. If the current through the rod is 1.73 ampere, then the value of B for which the rod remains stationary on the inclined plane is
|
(a) 1.73 Tesla |
(b) |
(c) 1 Tesla |
(d) None of the above |

A magnet of magnetic moment M is rotated through 360° in a magnetic field H, the work done will be
| (a) MH | (b) 2MH | (c) 2πMH | (d) Zero |
In producing a pure spectrum, the incident light is passed through a narrow slit placed in the focal plane of an achromatic lens because a narrow slit:
Energy stored in electromagnetic oscillations is in the form of
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(a) Electrical energy |
(b) Magnetic energy |
(c) Both (a) and (b) |
(d) None of these |
In double slit experiment, the angular width of the fringes is 0.20o for the sodium light (λ =5890 Å). In order to increase the angular width of the fringes by 10%, the necessary change in the wavelength is
|
(a) Increase of 589 Å |
(b) Decrease of 589 Å |
(c) Increase of 6479 Å |
(d) Zero |
A planet of mass m moves in an ellipse around the sun of mass so that its maximum and minimum distances are
and
respectively. The angular momentum of the planet relative to the centre of the sun is
|
(a) |
(b) |
(c) |
(d) |