NEET 2021 Model Test Paper 3

The force acting on a particle of mass M and charge q moving in uniform clectric field is given by
F=qE
Or Ma=qE or a=

qE

M

∴v=at=

qE

M

t
Using s=ut+

1

2

at2
=

1

2

(

qE

M

)t2‌‌‌‌‌ (∵u=0) .....(1)
Now, kinetic energy of particle
T=

1

2

Mv2=

1

2

M (

q E

M

t )2
=

1

2

( q E)2

M

t2 .....(2)
∴

T

s

=

1 2 ( q E)2 t2∕M

1 2 ( qE) t2∕M

= q E
i.e. ratio (T/s) remains constant with time t iscorrect answer is (a) :-