JEE Main 2020PhysicsUnits and DimensionsHardMCQ

JEE Main 2020 — Units and Dimensions Question with Solution

JEE Main 2020 (08 Jan Shift 1)

Question

The dimension of stopping potential V0 in photoelectric effect in units of Planck’s constant ‘ h ’, speed of light ‘ c ’ and Gravitational constant ‘ G ’ and ampere A is:

Choose an option

Show full solutionCorrect option: B
Correct answer
Bh0c5G-1A-1

Step-by-step explanation

V=K(h)a(I)b(G)c(C)d (V is voltage)
We know [h]=ML2T-1
[I]=A
[G]=M-1L3T-2
[C]=LT-1
[V]=ML2T-3A-1
ML2T-3A-1=(ML2T-1)a(A)b(M-1L3T-2)c(LT-1)d
ML2T-3A-1=Ma-cL2a+3c+dT-a-2c-dAb
a-c=1 .....(1)
2a+3c+d=2 .....(2)
-a-2c-d=-3 .....(3)
b=-1  ...(4)
On solving
c=-1
a=0
d=5, b=-1
V=K(h)0(A)-1(G)-1(C)5

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About this question

This is a previous-year question from JEE Main 2020, covering the Units and Dimensions chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.