Given,

Frequency (f) = 4.80 x 10¹³Hz = 4.80 x 10¹³/sec

Planck’s constant (h) = 6.626 x 10⁻³⁴ J.sec

Number of photons = ?

We know that:-

Energy (E) = planck’s constant (h) x frequency (f)

= 6.626 x 10⁻³⁴J.sec x 4.80 x 10¹³/sec

= 31.8 x 10⁻²¹J ≈ 32 x 10⁻²¹J

Energy (E) = 32 x 10⁻²¹J/photons

Number of photons for 1.16J

1.16J / 32 x 10⁻²¹J/photons = 0.03625 x 10²¹ ≈ 3.625 x 10¹⁹photons.