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
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