If the photon detector receives a total of 3.15$\times {10}^{-18}$ J from the radiation of 600 nm, the number of photons received by the detector would be: 

$1.$ ${10}^2$
$2.$ $10$
$3.$ $50$
$4.$ $20$

A 25-watt bulb emits monochromatic yellow light with a wave length of 0.57µm. The rate of emission of quanta per second would be :

1. 7.17 × 10^–19 s^–1

2. 4.13 × 10¹⁶ s^–1

3 . 7.17 × 10¹⁹ s^–1

4 . 1.26 × 10²⁰ s^–1
${\mathrm{}}^{}$