The sun emits a light with maximum wavelength 510 mm while another star X emits a light with maximum wavelength of 350 nm. What is the ratio of surface temperature of sun and the star X
|
(a) 2.1 |
(b) 0.68 |
(c) 0.46 |
(d) 1.45 |
(b) 0.68
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You are given four sources of light each one providing a light of a single colour – red, blue, green and yellow. Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incidence at the interface of two media is 90º. Which of the following statements is correct if the source of yellow light is replaced with that of other lights without changing the angle of incidence?
An electric bulb is rated 60W, 220V. The resistance of its filament is
|
(a) 708 W |
(b) 870 W |
(c) 807 W |
(d) 780 W |
If nearly 
coulomb liberate 1 gm equivalent of aluminium, then the amount of aluminium (equivalent weight 9) deposited through electrolysis in 20 minutes by a current of 50 amp will be
|
(a) 0.6 gm |
(b) 0.09 gm |
(c) 5.4 gm |
(d) 10.8 gm |
Consider a radioactive material of half-life 1.0 minute. If one of the nuclei decays now, the next one will decay
|
(a) After 1 minute |
|
(b) After |
|
(c) After |
|
(d) After any time |
In Young's double slit experiment, the slits are 0.5 mm apart and interference pattern is observed on a screen placed at a distance of 1.0 m from the plane containing the slits. If wavelength of the incident light is 6000 Å, then the separation between the third bright fringe and the central maxima is
|
(a) 4.0 mm |
(b) 3.5 mm |
(c) 3.0 mm |
(d) 2.5 mm |
Work done in moving a positive charge on an equipotential surface is
|
(a) Finite, positive but not zero |
(b) Finite, negative but not zero |
|
(c) Zero |
(d) Infinite |
A wire of length 5 m and radius 1 mm has a resistance of 1 ohm. What length of the wire of the same material at the same temperature and of radius 2 mm will also have a resistance of 1 ohm
|
(a) 1.25 m |
(b) 2.5 m |
(c) 10 m |
(d) 20 m |
