Answer:
Only magnetic field present
Explanation:
Since, the positively charged particle does not speed up or slow down, but it does deflect in the downward direction. Â This means only magnetic field is present.
This is because electric field changes the velocity and magnetic field changes the direction.
The magnetic force F is given by
F = qvBsinθ
Where, q = charge magnitude, v = velocity of charge, B = strength of magnetic field. and θ =the angle between the directions of v and B.