A fringe width of a certain interference pattern is β=0.002 cm. What is the distance of 5th dark fringe centre?
Options
(a) 1×10⁻² cm (b) 11×10⁻² cm (c) 1.1×10⁻² cm (d) 3.28×10⁶ cm
A beam of light of wavelength 590 nm is focussed by a converging lens of diameter 10 cm at a distance of 20 cm form it. Find the diameter of the disc image formed
Efficiency of a Carnot engine is 50% when temperature of sink is 500K. In order to increase efficiency up to 60% keeping temperature of source remains the same, temperature of sink is
Options
A Carnot engine takes heat from a reservoir at 627⁰C and rejects heat to a sink at 27⁰C. Its efficiency will be
Options
(a) (3/5) (b) (1/3) (c) (2/3) (d) (200/209)
Correct Answer: […]
Two thin lenses when placed in contact, then the power of combination is +10 D. If they are kept 0.25 m apart, then the power reduces to +6 D. The focal lengths of the lenses […]
The mirrors are inclined at an angle of 50⁰. The number of images formed for an object placed in between the mirrors is
Options
(a) 5 (b) 6 (c) 7 (d) 8
Correct […]
An α-particle of energy 5 MeV is scattered through 180⁰ by a fixed uranium nucleus. The distance of the closest approach is of the order of
Options
(a) 1Å (b) 10⁻¹⁰ cm (c) […]
The half-life of radioactive element is 600 yr. The fraction of sample that would remain after 3000 yr is
Options
(a) (1/2) (b) (1/16) (c) (1/8) (d) (1/32)
Correct Answer:
(1/32)
Explanation:
No […]
If the terminal speed of a sphere of gold (density=19.5 kg/m³) is 0.2 m/s in a viscous liquid (density=1.5 kg/m³) find the terminal speed of a sphere of silver (density 10.5 kg/m³) of the same […]
A black body at a temperature of 227⁰C radiates heat at a rate of 20 cal m⁻²s⁻¹. When its temperature is raised to 727⁰C, the heat radiated by it in cal m⁻²s⁻¹ will be closest […]
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