Question
A conducting sphere of radius R carries a charge Q. If
half of the charge is transferred to an identical uncharged sphere brought into contact and removed, the electrostatic energy of the system becomes:Solution
The electrostatic energy (U) of a charged conducting sphere is given by: 
When the charged sphere (with charge Q) is brought into contact with an identical uncharged sphere, the charge will be equally distributed between them due to their identical nature and conducting property.
- Each sphere will have a charge of Q/2.
So, the final electrostatic energy of the system is half of the original electrostatic energy. Therefore, the correct answer is (a) Half of original.
Find the missing number in the given number series.
58, 86, 142, ?, 478, 926
7, 6, 10, 27, 104, ?
Find the missing number (?) in the given number series.
2, 6, 18, 54, ?, 486
A series given below follows a certain pattern,
1800, 469, (?), 855, 980, 953
If (?) = B – 2, then find the nearest cube root of B.
142, 148, 160, 178, ?, 232
15.975 ×27.825 + (76.01)² + 12.98×18.426 = ?+ (79.09)²
43, 56, 82, ?, 173, 238
4, 9, 24, 69, ?, 609
2, 2, 6, 30, ?, 1890
Find the missing number in the given number series.
3, 7, 18, 38, 69, ?
Relevant for Exams:
