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:
If the photon detector receives a total of 3.15 J from the radiation of 600 nm,
the number of photons received by the detector would be:
The neon gas emits radiation of 616 nm. The number of quanta that are present in 2 J of energy is:
The wavelength of the light emitted when the electron returns to the ground state in the H atom, from n = 5 to n = 1, would be: (The ground-state electron energy is –2.18 × 10-18 j)
1. Wavelength = 9.498 x 10-8 km
2. Wavelength = 12.498 x 10-8 m
3. Wavelength = 9.498 x 10-8 m
4. Wavelength = 9.498 x 10-8 cm
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. 4.13×1016s-1
3 . 7.17×1019 s-1
4 . 1.26 ×1020s-1
The number of photons of light with a wavelength of 4000 pm that provide 1J of energy would be:
A radiation source emitted 2.5 × 1015 photons in 2 nanoseconds. Energy of the source is -
Assertion (A): | A black body is an ideal body that emits and absorbs radiation of all frequencies. |
Reason (R): | The frequency of radiation emitted by a body goes from lower frequency to a higher frequency with an increase in temperature. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
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