A charged ball of mass m and charge q is...

A charged ball of mass m and charge q is projected from the ground with an initail velocity u and angle of projection `theta` at the time of projection vertically upward electric field E is switched on. When it reaches the maximum height electric filed is switched off and a horizontal electric feild of same magnitude E is switched on. Then answer the following question (Assume mg> qE)
Q In the above experiment

horizionatl velocity always remains constant

horizontal velocity remains constant for hall of the time and then varies.

horizontal velocity when it strikes the grounds is greater than the intial horizontal velocity

the initial vertical speed is equal to the final vertical speede.

Verified by Experts

The correct Answer is:

A charged ball of mass m and charge q is projected from the ground with an initail velocity u and angle of projection theta at the time of projection vertically upward electric field E is switched on. When it reaches the maximum height electric filed is switched off and a horizontal electric feild of same magnitude E is switched on. Then answer the following question (Assume mg> qE) Q If the time of flight to the maximum height is t_1 and the time of flight maximum height to the ground is t_2 then

`t_1=t_2`

`t_1ltt_2`

`t_1gtt_2`

none of these

Its velocity at half the maximum height is `sqrt3/2u`

Its velocity at the maximum height is `u`

Change in its velocity when it returns to the ground is `u`

all the above are true

`u cos theta` downward

`u cos theta` upward

`u sin theta` upward

`u sin theta` downward