Question

Let $n_r$ and $n_b$ be respectively the number of photons emitted by a red bulb and a blue bulb of equal power in a given time, then:

• A. $n_r=n_b$
• B. $n_r<n_b$
• C. $n_r>n_b$
• D. data insufficient

Answer 1

The correct option is C $n_r>n_b$

$n_r\frac{hc}{{\lambda }_r}=n_b\frac{hc}{{\lambda }_b}$

$n_r=\frac{{\lambda }_r}{{\lambda }_b}{n}_b$

as ${\lambda }_r>{\lambda }_b$

$\therefore n_r>n_b$