A metal cube of side 5 cm is charged with 6 μ C . The surface charge density on the cube is

Correct answer: D. 0.4 × 10^ -3 C m^ -2 In metal all the charge is present on surface. Q=6 μ C Total surface area S=6 a^2 =6 × (5 × 10^ -2 )^2 =6 × 25 × 10^ -4 =150 × 10^ -4 ~m^2 Surface charge density σ=(Q)/(S) = 6 × 10^ -6 150 × 10^ -4 =0.4 × 10^ -3 C m^ -2

NEET 2024

Exam: NEET
Year: 2024
Subject: Physics
Chapter: Electrostatics

NEET 2024 · Physics · Electrostatics

A metal cube of side 5 cm is charged with 6 μ C . The surface...

A metal cube of side 5 cm is charged with

6 \mu \mathrm{C}

. The surface charge density on the cube is

Options

A $0.125 \times 10^{-3} \mathrm{C} \mathrm{m}^{-2}$
B $0.25 \times 10^{-3} \mathrm{C} \mathrm{m}^{-2}$
C $4 \times 10^{-3} \mathrm{C} \mathrm{m}^{-2}$
D $0.4 \times 10^{-3} \mathrm{C} \mathrm{m}^{-2}$

Correct answer

D. $0.4 \times 10^{-3} \mathrm{C} \mathrm{m}^{-2}$

Step-by-step solution

\Rightarrow

In metal all the charge is present on surface.

Q=6 \mu C

Total surface area

S=6 a^2 =6 \times

\left(5 \times 10^{-2}\right)^2

=6 \times 25 \times 10^{-4}

=150 \times 10^{-4} \mathrm{~m}^2

Surface charge density

\sigma=\frac{Q}{S}

=\frac{6 \times 10^{-6}}{150 \times 10^{-4}}

=0.4 \times 10^{-3} \mathrm{C} \mathrm{m}^{-2}

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