One gram mass falls through a height of 2cm. If whole of the energy of fall is converted into light of wavelength `6.63xx10^(-7)m`, how many photons would be produced? Given `h=6.63xx10^(-7)Js g=10m//s^(2)`

Options

A. `3.33xx10^(14)`
B. `3.33xx10^(15)`
C. `6.67xx10^(14)`
D. `6.67xx10^(15)`

Answer

c

Explanation

Here, `m=1g=10^(-3)kg, h=2 cm =2xx10^(-2)m`
Energy of fall, `E=mgh=10^(-3)xx10xx2xx10^(-2)`
`=2xx10^(-4)J`
Energy of each photon, `E'=(hc)/lambda`
No. of photons produeced, `n=E/(E')=(Elambda)/(hc)`
`=((2xx10^(-4))(6.63xx10^(-7)))/((6.63xx10^(-34))xx(3xx10^(8)))=6.67xx10^(14)`