A nitrogen laser produces radiation at a wavelength of 337.1 nm. If the number of photons emitted is 5.6 × 10²⁴,
the power of the laser is:

$\mathrm{}$$1.$ $4.56$ $\times$ ${10}^7$ $\mathrm{J}$
$2.$ $3.33$ $\times$ ${10}^6$ $\mathrm{J}$
$3.$ $1.29$ $\times$ ${10}^6$ $\mathrm{J}$
$4.$ $9.17$ $\times$ ${10}^5$ $\mathrm{J}$

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: 

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

The neon gas emits radiation of 616 nm. The number of quanta that are present in 2 J of energy is:

1. \(6.2 \times 10^{-18} \)
2. \(5.6 \times 10^{17} \)
3. \(6.2 \times 10^{18} \)
4. \(32.2 \times 10^{-20}\)

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
${\mathrm{}}^{}$

The number of photons of light with a wavelength of 4000 pm that provide 1J of energy would be: 

$1.$ $2.01$ $\times$ ${10}^{16}$
$2.$ $2.01$ $\times$ ${10}^{19}$
$3.$ $4.14$ $\times$ ${10}^{23}$
$4.$ $2.14$ $\times$ ${10}^{21}$

A radiation source emitted  2.5 × 10¹⁵ photons in 2 nanoseconds. Energy of the source is :

$1.$ $8.28$ $\times$ ${10}^{-10}$ $\mathrm{J}$
$2.$ $8.24$ $\times$ ${10}^{10}$ $\mathrm{J}$
$3.$ $7.12$ $\times$ ${10}^{-11}$ $\mathrm{J}$
$4.$ $2.12$ $\times$ ${10}^{}$ $10$ $\mathrm{J}$

Electromagnetic radiation of wavelength 242 nm is just sufficient to ionise sodium atom. The ionisation energy of sodium in kJ mol^–1 is :

1. 494

2. 4.94

3. 516

4. 0.50