Answer:
The radius of the sphere is 3.6 m.
Explanation:
Given that,
Potential of first sphere = 450 V
Radial distance = 7.2 m
If the potential of sphere =150 V
We need to calculate the radius
Using formula for potential
For 450 V

....(I)
For 150 V
....(II)
Divided equation (I) by equation (II)





Hence, The radius of the sphere is 3.6 m.
PART A)
If we increase the voltage supply in an electromagnet then it will increase the current that is flowing in it
So here due to increase in current there will be increase in the magnetic field due to that electromagnet
PART B)
Here in electric generator the current is produced by rotating a coil between two strong magnets.
So here mechanical energy of rotation of coil is converted into electromagnetic energy.
PART C)
Step up transformer convert the lower voltage input into higher voltage output
here number of turns of coil in output side or secondary number of coils is more than the number of coils in primary side or input side
PART D)
Force on a moving charge is given by

here we know that
q = 0.000600 C

B = 4.21 T
now from above equation we have


direction of force is given by right hand thumb rule
using that rule we got force downwards
Before getting an answer for it first we have to understand nuclear fusion.
Nuclear fusion is a thermo-nuclear reaction in which two light unstable nuclei will form a heavy stable nuclei. In this process there will be some mass defect which will be converted into energy as per Einstein's mass energy equivalence theorem.
The theorem is stated as
where c is the velocity of light and m is the mass converted into energy.
One take an example of fusion in sun where 4 hydrogen atoms combine to form a helium nucleus which are explained below-



-----------------------------------------------------------------------
Here
is the positron.
In this process very high temperature is needed which is approximately equal to the temperature of the sun i.e 
Such temperature is very difficult to initiate the reaction on the earth surface. It should be carried out in an sustainable way also .Otherwise It will cause nuclear hazards.
Answer:
A book on its side exerts a greater force.
Explanation:
Pressure = Force / Area
Assuming that 1kg = 10N
2kg = 20N
Area of book lying flat = 0.3m × 0.2m
= 0.6m²
Pressure of book lying flat = 20N / 0.6m²
= 30Pa (1 s.f.)
Area of book on its side = 0.2m × 0.05m
= 0.01m²
Pressure of book on its side = 20N / 0.01m²
= 2000Pa (1 s.f.)
Since 2000Pa (1 s.f.) > 30Pa (1 s.f.), a book on its side applies greater pressure than lying flat.
Answer:
a) 4.45 m/s
b) 0.9 seconds
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.81 m/s²

a) The vertical speed when the player leaves the ground is 4.45 m/s

Time taken to reach the maximum height is 0.45 seconds

Time taken to reach the ground from the maximum height is 0.45 seconds
b) Time the player stayed in the air is 0.45+0.45 = 0.9 seconds