- AInfrared rays
- BMicrowaves
- CRadiowaves
- DX-Rays
Explanation:
Microwaves are used by artificial satellites for communication.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
The charges on two sphere are +7mC and – 5mC respectively. They experience a force F. If each of them is given and additional charge of – 2mC, the new force of attraction will be
|
(a) F |
(b) F / 2 |
(c) F/ |
(d) 2F |
Consider a parallel plate capacitor of 10 μF (micro-farad) with air filled in the gap between the plates. Now one half of the space between the plates is filled with a dielectric of dielectric constant 4, as shown in the figure. The capacity of the capacitor changes to
|
(a) 25 μF |
(b) 20 μF |
(c) 40 μF |
(d) 5 μF |
Dual nature of radiation is shown by
|
(a) Diffraction and reflection |
(b) Refraction and diffraction |
|
(c) Photoelectric effect alone |
(d) Photoelectric effect and diffraction |
What happens to the force between magnetic poles when their pole strength and the distance between them are both doubled
|
(a) Force increases to two times the previous value |
|
(b) No change |
|
(c) Force decreases to half the previous value |
|
(d) Force increases to four times the previous value |
A triode whose mutual conductance is 2.5 m A/volt and anode resistance is 20 kilo ohm, is used as an amplifier whose amplification is 10. The resistance connected in plate circuit will be
|
(a) 1 kW |
(b) 5 kW |
(c) 10 kW |
(d) 20 kW |
Four wires of equal length and of resistances 10 ohms each are connected in the form of a square. The equivalent resistance between two opposite corners of the square is
|
(a) 10 ohm |
(b) 40 ohm |
(c) 20 ohm |
(d) 10/4 ohm |
A parallel plate capacitor with air as medium between the plates has a capacitance of 10 μF. The area of capacitor is divided into two equal halves and filled with two media as shown in the figure having dielectric constant and
. The capacitance of the system will now be
|
(a) 10 μF |
(b) 20 μF |
(c) 30 μF |
(d) 40 μF |