Question

class 11 .please answer in detail​

Answer 1

$74.93 \times {10}^{ - 19} J$

Explanation:

$Given, \: v = 2 \times {10}^{16} Hz \: \: and \: \: v _{o} = 8.68 \times {10}^{15} Hz \\ we \: \: know \: \: that \: \: \boxed{KE = hv - hv _{o}} \\ KE = h(v - v_{o} ) \\ putting \: \: value \: \: h = 6.62 \times {10}^{ - 34} Js \: \: (plank's constant) \\ Now, \: \: KE=6.62 \times {10}^{ - 34} \times (2 \times \times {10}^{16} - 8.68 \times {10}^{15} ) \\ = 6.62 \times {10}^{ - 34} (20 \times {10}^{15} - 8.68 \times {10}^{15} ) \\ = 6.62 \times {10}^{ - 34} \times 11.32 \times {10}^{15} \\ = 74.93 \times {10}^{ - 19} J$