Two insulated metal spheres of raddi 10 cm and 15 cm charged to a potential of 150 V and 100 V respectively, are connected by means of a metallic wire. What is the charge on the first sphere?

Options

A. 2 esu
B. 4 esu
C. 6 esu
D. 8 esu

Answer

B

Explanation

Here, `r_(1)=10cm, r_(2)=15cm, V_(1)=150V, V_(2)=100V`
Common potential,
`V=(C_(1)V_(1)+C_(2)V_(2))/(C_(1)+C_(2))=(4pi epsilon_(0)(r_(1)V_(1)+r_(2)V_(2)))/(4pi epsilon_(0)(r_(1)+r_(2))=120V`
`therefore" "q_(1)=C_(1)V=4pi epsilon_(0)r_(1)V=(10^(-1))/(9xx10^(9))xx120C`
`=(12)/(9xx10^(9))xx3xx10^(9)"esu = 4 esu"`