- AInfrared rays
- BUltraviolet rays
- CMicrowaves
- DX-rays
Explanation:
Microwaves have wavelength around 10cm.
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An electric current passes through a long straight wire. At a distance 5 cm from the wire, The magnetic field is B. The field at 20 cm from the wire would be
|
(a) |
(b) |
(c) |
(d) |
A lens (focal length 50 cm) forms the image of a distant object which subtends an angle of 1 milliradian at the lens. What is the size of the image
|
(a) 5 mm |
(b) 1 mm |
(c) 0.5 mm |
(d) 0.1 mm |
The internal resistance of a cell depends on
|
(a) The distance between the plates |
(b) The area of the plates immersed |
|
(c) The concentration of the electrolyte |
(d) All the above |
If the refractive indices of a prism for red, yellow and violet colours be 1.61, 1.63 and 1.65 respectively, then the dispersive power of the prism will be
|
(a) |
(b) |
(c) |
(d) |
Consider an extended object immersed in water contained in a plane trough. When seen from close to the edge of the trough the object looks distorted because:
An electric field of 1500 V / m and a magnetic field of 0.40 weber / meter2 act on a moving electron. The minimum uniform speed along a straight line the electron could have is
|
(a) 1.6 × 1015 m / s |
(b) 6 × 10-16 m / s |
(c) 3.75 × 103 m / s |
(d) 3.75 × 102 m / s |
A diamagnetic material in a magnetic field moves
|
(a) From weaker to the stronger parts of the field |
|
(b) Perpendicular to the field |
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(c) From stronger to the weaker parts of the field |
|
(d) In none of the above directions |
Some electric bulbs are connected in series across a 220 V supply in a room. If one bulb is fused then remaining bulbs are connected again in series across the same supply. The illumination in the room will
|
(a) Increase |
(b) Decrease |
(c) Remains the same |
(d) Not continuous |