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

• A. $n_{r}=n_{b}$
• B. $n_{r} < n_{b}$
• C. $n_{r}>n_{b}$
• D. the information is insufficient to get a relation between $n_{r}$ and $n_{b}$

Answer 1

Answer: (C)

$P_{R e d}=P_{B l u e}$
$n_{r}\frac{h c}{\lambda _{r}}=n_{b}\frac{h c}{\lambda _{b}}$
$\frac{n_{r}}{n_{b}}=\frac{\lambda _{r}}{\lambda _{b}}$
As $\lambda _{r}>\lambda _{b}$
$\therefore $ $n_{r}>n_{b}$