Two insulated charged conducting spheres of radii 20 cm and 15 cm respecting and having an equal charge of 10 $μ C$ are connected by a copper wire and then they are separated. Then

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

Both spheres will have equal charges

Surface charge density on the 20 cm sphere will be greater than that on the 15 cm sphere

Surface charge density on the 15 cm sphere will be greater than that on the 20 cm sphere

Surface charge density on the two sphere will be equal

answer is C.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

$V_{1} = V_{2} \Rightarrow \frac{10 + q}{20} = \frac{10 - q}{15}$
$\begin{array}{l} 30 + 3 q = 40 - 4 q \\ 7 q = 10 \\ q = \frac{10}{7} μ C \end{array}$
$\Rightarrow$ charge on $20 μ C = (10 + \frac{10}{7}) μ C$
Surface charge density of $20 μ C Q_{1} = \frac{\frac{80}{7} μ C}{4 π \times {(20 \times 10^{- 2})}^{2}}$
Surface charge density of $\begin{array}{l} 15 μ C Q_{2} = \frac{\frac{60}{7} μ C}{4 π \times {(15 \times 10^{- 2})}^{2}} \\ σ_{2} > σ_{1} \end{array}$