1
KCET 2023
MCQ (Single Correct Answer)
+1
-0

The energy gap of an LED is $$2.4 \mathrm{~eV}$$. When the LED is switched ON, the momentum of the emitted photons is

A
$$1.28 \times 10^{-27} \mathrm{~kg} \mathrm{~ms}^{-1}$$
B
$$2.56 \times 10^{-27} \mathrm{~kg} \mathrm{~ms}^{-1}$$
C
$$1.28 \times 10^{-11} \mathrm{~kg} \mathrm{~ms}^{-1}$$
D
$$0.64 \times 10^{-27} \mathrm{~kg} \mathrm{~ms}^{-1}$$
2
KCET 2022
MCQ (Single Correct Answer)
+1
-0

The kinetic energy of the photoelectrons increases by $$0.52 \mathrm{~eV}$$ when the wavelength of incident light is changed from $$500 \mathrm{~nm}$$ to another wavelength which is approximately

A
400 nm
B
1250 nm
C
1000 nm
D
700 nm
3
KCET 2022
MCQ (Single Correct Answer)
+1
-0

The de-Broglie wavelength of a particle of kinetic energy $$K$$ is $$\lambda$$, the wavelength of the particle, if its kinetic energy $$\frac{K}{4}$$ is

A
$$2 \lambda$$
B
$$\frac{\lambda}{2}$$
C
$$4 \lambda$$
D
$$\lambda$$
4
KCET 2022
MCQ (Single Correct Answer)
+1
-0

In a photo electric experiment, if both the intensity and frequency of the incident light are doubled, then the saturation photoelectric current

A
is halved
B
is doubled
C
becomes four times
D
remains constant
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