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Solid angle subtended by hemisphere at c...

Solid angle subtended by hemisphere at centre is ...... .

A

1sr

B

`2pi sr`

C

`4pi sr`

D

`pi sr`

Text Solution

Verified by Experts

Surface area of sphere of radius `r=4pi r^(2)`
`:.` Surface are of hemisphere `DeltaA=2pi r^(2)`
`:.` Solid angle `=(DeltaA)/(r^(2))=(2pir^(2))/(r^(2))=2pi sr`
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