 Solution

ID: past-exam-of-the-physics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2014/paper-1/a1/solution

h f

\dot{N} = \frac{P}{h f} = 8.38 \times 1 0^{22} s^{- 1}, λ = \frac{c}{f} = 0.167 m .

Here

P

is radiated signal power, not the phone's total electrical consumption.

 New to topics? Read the docs here!