Which of the following statements is false ?
(1) A rheostat can be used as a potential divider.
(2) Kirchhoff's second law represents energy conservation.
(3) Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.
(4) In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.
(1) A rheostat can be used as a potential divider.
(2) Kirchhoff's second law represents energy conservation.
(3) Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.
(4) In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.
- (A)A rheostat can be used as a potential divider.
- (B)Kirchhoff's second law represents energy conservation.
- (C)Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.
- (D)In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.✓ Correct
Answer: (D)
Solution
Run through the claims one at a time. A rheostat wired with three terminals genuinely works as a potential divider, so that is true. Kirchhoff's loop rule is a statement of energy conservation around a closed path, true as well. A Wheatstone bridge really is most sensitive when all four resistances are of comparable magnitude, true again. The faulty one is the last: in a balanced bridge the balance condition is symmetric in the cell and the galvanometer, so interchanging them leaves the null point exactly where it was. That is the false statement.
JEE Main · 2017 · 02 Apr 2017 · Offline · Single correct option