- AOrder of colours is reverse
- BOrder of colours is irregular
- CColours are overlapped
- DNo colours is present
Explanation:
The order of colours is are straight, hence option a is false.
Order of colours are regular.
Colours are overlapped each other in impure spectrum.
Colours are present in impure spectrum.
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A triangular loop of side l carries a current I. It is placed in a magnetic field B such that the plane of the loop is in the direction of B. The torque on the loop is
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(a) Zero |
(b) IBl |
(c) |
(d) |
The electric intensity due to a dipole of length 10 cm and having a charge of 500μC, at a point on the axis at a distance 20 cm from one of the charges in air, is
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(a) 6.25 |
(b) 9.28 |
(c) 13.1 |
(d) |
Assertion : Microwave propagation is better than the sky wave propagation.
Reason : Microwaves have frequencies 100 to 300 GHz, which have very good directional properties.
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(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. |
Consider the following two statements A and B, and identify the correct choice out of given answers
A. Thermo e.m.f. is minimum at neutral temperature of a thermocouple
B. When two junctions made of two different metallic wires are maintained at different temperatures, an electric current is generated in the circuit.
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(a) A is false and B is true |
(b) A is true and B is false |
|
(c) Both A and B are false |
(d) Both A and B are true |
GaAs is
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(a) Element semiconductor |
(b) Alloy semiconductor |
|
(c) Bad conductor |
(d) Metallic semiconductor |
Magnetic fields at two points on the axis of a circular coil at a distance of 0.05m and 0.2m from the centre are in the ratio 8 : 1. The radius of the coil is
|
(a) 1.0 m |
(b) 0.1 m |
(c) 0.15 m |
(d) 0.2 m |