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It takes 20 s for a person A of mass 50 kg to climb up the stairs, while another person B of same mass does the same in 15 s. Compare the power developed by the persons A and B.
Concept: undefined >> undefined
A man raises a box of mass 50 kg to a height of 2 m in 20s, while another man raises the same box to the same height in 50s. Calculated:
- the work done, and
- the power developed by each man. Take g = 10 N kg-1.
Concept: undefined >> undefined
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A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes. Compare:
- the work, and
- power developed by them.
Concept: undefined >> undefined
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes.
How much work each does? Take density of water = 103 kg m-3 and g = 9.8 N kg-1.
Concept: undefined >> undefined
An obliquely incident light ray bends at the surface due to a change in speed when passing from one medium to another. The ray does not bend when it is incident normally. Will the ray have a different speed in the other medium?
Concept: undefined >> undefined
Compare the speeds of light of wavelength 4000 Å (i.e. violet light) and 8000 Å (i.e. red light) in vacuum.
Concept: undefined >> undefined
State the name and the range of wavelength of the invisible electromagnetic waves beyond the red end of the visible spectrum.
Concept: undefined >> undefined
Name three radiations and their wavelength range which are invisible and beyond the violet end of the visible spectrum.
Concept: undefined >> undefined
Name the radiation which can be detected by thermopile.
Concept: undefined >> undefined
Higher the current rating, _______ is the fuse wire.
Concept: undefined >> undefined
How does the thickness of a fuse wire depend on its current rating?
Concept: undefined >> undefined
The rating of a fuse connected in the lighting circuit is ______.
Concept: undefined >> undefined
To which regions of the electromagnetic spectrum do the following wavelengths belong:
(a) 250 nm
(b) 1500 nm
Concept: undefined >> undefined
Calculate the shortest wavelength of electromagnetic radiation present in Balmer series of hydrogen spectrum.
Concept: undefined >> undefined
State and define the unit of force in the S.I. system.
Concept: undefined >> undefined
How is 1 kgf related to the SI unit of force?
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What is the work done by the gravitational force on the moon that revolves around the earth?
Concept: undefined >> undefined
A bullet fired against a window glass pane makes a hole in it without any cracks while a stone striking the same glass pane smashes it; explain with reason.
Concept: undefined >> undefined
Give the units of couple.
Concept: undefined >> undefined
