1) 
When both the electric field and the magnetic field are acting on the electron normal to the beam and normal to each other, the electric force and the magnetic force on the electron have opposite directions: in order to produce no deflection on the electron beam, the two forces must be equal in magnitude
where
q is the electron charge
E is the magnitude of the electric field
v is the electron speed
B is the magnitude of the magnetic field
Solving the formula for v, we find
2) 4.1 mm
When the electric field is removed, only the magnetic force acts on the electron, providing the centripetal force that keeps the electron in a circular path:
where m is the mass of the electron and r is the radius of the trajectory. Solving the formula for r, we find
3) 
The speed of the electron in the circular trajectory is equal to the ratio between the circumference of the orbit, 
, and the period, T:
Solving the equation for T and using the results found in 1) and 2), we find the period of the orbit:
Explanation :
The interaction between two objects is termed as the collision. The collision can be of two types i.e. elastic collision and inelastic collision.
In this case, two identical carts travel at the same speed toward each other, and then a collision occurs. In an inelastic collision, the momentum before and after the collision remains the same but its kinetic energy gets lost.
After the collision, both the object sticks over each other and moves with one velocity.
Out of the given graph, the graph that shows a perfectly inelastic collision is attached. It shows that after the collision both the carts move with the same velocity.
Answer:
Snail's speed = 
= 0.0125m/s
Turtle's speed = 
= 0.1375m/s
Explanation:
Let the snail's speed be x m/s
The turtle's speed then is 11x m/s
Speed = Distance ÷ Time
Since speed and distance are directly proportional;
The ratio of the distances snail and turtle cover before they meet is x:11x respectively.
Simplified, the ratio of snail distance : turtle distance = 1:11
So snail covers a distance of 
× 360 = 30m
And turtle covers a distance of 
× 360 = 330m
The time each took before they met is 40 × 60 = 2400 seconds
Snail's speed = = 0.0125m/s
Turtle's speed = = 0.1375m/s
By law of refraction we know that image position and object positions are related to each other by following relation
here we know that
now by above formula
so apparent depth of the bottom is seen by the observer as h = 3.39 cm
with the same generator, so the only factor for producing
the slectric field is only the speed. The faster the rotational speed of the
generator the greater it produce electric field. So the sequence is 3000 rpm
< 3200 rpm < 3400 rpm < 3600 rpm
