Electricity
Current Electricity
MCQ (Single Correct Answer)
Moving Charges and Magnetism
MCQ (Single Correct Answer)
Magnetism and Matter
MCQ (Single Correct Answer)
Electromagnetic Induction
MCQ (Single Correct Answer)
Electromagnetic Waves
MCQ (Single Correct Answer)
Modern Physics
Semiconductor Electronics
MCQ (Single Correct Answer)
1
NEET 2022 Phase 1
MCQ (Single Correct Answer)
+4
-1

When two monochromatic lights of frequency, v and $${v \over 2}$$ are incident on a photoelectric metal, their stopping potential becomes $${{{V_s}} \over 2}$$ and Vs respectively. The threshold frequency for this metal is

A
2v
B
3v
C
$${2 \over 3}$$v
D
$${3 \over 2}$$v
2
NEET 2021
MCQ (Single Correct Answer)
+4
-1
The number of photons per second on an average emitted by the source of monochromatic light of wavelength 600nm, when it delivers the power of 3.3 $$\times$$ 10$$-$$3 watt will be : (h = 6.6 $$\times$$ 10$$-$$34 Js)
A
1015
B
1018
C
1017
D
1016
3
NEET 2021
MCQ (Single Correct Answer)
+4
-1
An electromagnetic wave of wavelength '$$\lambda$$' is incident on a photosensitive surface of negligible work function. If 'm' mass is of photoelectron emitted from the surface has de-Broglie wavelength $$\lambda$$d, then :
A
$$\lambda = \left( {{{2h} \over {mc}}} \right){\lambda _d}^2$$
B
$$\lambda = \left( {{{2m} \over {hc}}} \right){\lambda _d}^2$$
C
$${\lambda _d} = \left( {{{2mc} \over h}} \right){\lambda ^2}$$
D
$$\lambda = \left( {{{2mc} \over h}} \right){\lambda _d}^2$$
4
NEET 2020 Phase 1
MCQ (Single Correct Answer)
+4
-1
Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?
A
four times
B
one-fourth
C
zero
D
doubled
NEET Subjects