1.

If a vector `vec(A)` make angles `alpha , beta ` and `gamma`, respectively , with the `X , Y` and `Z` axes , then `sin^(2) alpha + sin^(2) beta + sin^(2) gamma =`A. `0`B. `1`C. `2`D. `3`

Answer» Correct Answer - C
`cos^(2) alpha + cos^(2) beta + cos^(2) gamma = 1`
`1 - sin^(2) alpha + 1 - sin^(2) beta + 1 - sin^(2) gamma = 1`
`sin^(2) alpha + sin^(2) beta + sin^(2) gamma = 2`


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