An electron falls from rest through a vertical
distance h in a uniform and vertically upward
directed electric field E. The direction of electric
field is now reversed, keeping its magnitude the
same. A proton is allowed to fall from rest in it
through the same vertical distance h. The time
of fall of the electron, in comparison to the time
of fall of the proton is
A
smaller
B
5 times greater
C
10 times greater
D
equal
2
NEET 2018
MCQ (Single Correct Answer)
+4
-1
A toy car with charge q moves on a frictionless
horizontal plane surface under the influence of
a uniform electric field $$\overrightarrow E $$
. Due to the force q$$\overrightarrow E $$
,
its velocity increases from 0 to 6 m s–1 in one
second duration. At that instant the direction of
the field is reversed. The car continues to move
for two more seconds under the influence of this
field. The average velocity and the average speed
of the toy car between 0 to 3 seconds are
respectively
A
2 m s–1, 4 m s–1
B
1 m s–1, 3 m s–1
C
1 m s–1, 3.5 m s–1
D
1.5 m s–1, 3 m s–1
3
NEET 2017
MCQ (Single Correct Answer)
+4
-1
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
4
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)
