Answer:
The time is
Explanation:
From the question we are told that
The height of the platform where the ball was dropped from is s = 215 m
The acceleration due to gravity is 
Generally from kinematic equations

Here u is the initial velocity of the ball and the value is u = 0 m/s given that the ball was at rest before it was dropped
So

=> 
=> 
=>
Physical change and I think you mean soaked.
Answer:
the strength of the magnetic field is 3 x 10⁻⁵ T
Explanation:
Given;
velocity of the cosmic ray, v = 5 x 10⁷ m/s
force experienced by the ray, f = 1.7 x 10⁻¹⁶ N
angle between the ray's velocity and the magnetic field, θ = 45⁰
The strength of the magnetic field is calculated as;

Therefore, the strength of the magnetic field is 3 x 10⁻⁵ T

The product in a chemical reaction is written on the Right side of the arrow, so
the product formed here in given reaction is :
Answer:
Where the electric potential is constant, the strength of the electric field is zero.
Explanation:
As a test charge moves in a given direction, the rate of change of the electric potential of the charge gives the potential gradient whose negative value is the same as the value of the electric field. In other words, the negative of the slope or gradient of electric potential (V) in a direction, say x, gives the electric field (Eₓ) in that direction. i.e
Eₓ = - dV / dx ----------(i)
From equation (i) above, if electric potential (V) is constant, then the differential (which is the electric field) gives zero.
<em>Therefore, a constant electric potential means that electric field is zero.</em>