Suppose the charge of a proton and an electron differ slightly. One of them is $$-$$e, the other is (e + $$\Delta $$e). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (musch greater than atomic size) apart is zero, then $$\Delta $$e is of the order of
[Given : mass of hydrogen mh = 1.67 $$ \times $$ 10$$-$$27 kg]
A
10$$-$$23 C
B
10$$-$$37 C
C
10$$-$$47 C
D
10$$-$$20 C
2
NEET 2017
MCQ (Single Correct Answer)
+4
-1
The diagrams below show regions of equipotentials.
A positive charge is moved from A to B in each diagram.
A
In all the four cases the work done is the same.
B
Minimum work is required to move q in figure(I).
C
Maximum work is required to move q in figure (II).
D
Maximum work is required to move q in figure (III)
3
NEET 2017
MCQ (Single Correct Answer)
+4
-1
The resistance of a wire is 'R' ohm. If it is melted and stretched to 'n' times its original length. its new resistance will be
A
$${R \over n}$$
B
n2R
C
$${R \over {{n^2}}}$$
D
nR
4
NEET 2017
MCQ (Single Correct Answer)
+4
-1
A potentiometer is an accurate and versatile device to make electrical measurements of EMF because the method involves
A
potential gradients
B
a condition of no current flow through the galvanometer
C
a combination of cells, galvanometer and resistances
