Answer:
Given the area A of a flat surface and the magnetic flux through the surface 
it is possible to calculate the magnitude 
.
Explanation:
The magnetic flux gives an idea of how many magnetic field lines are passing through a surface. The SI unit of the magnetic flux is the weber (Wb), of the magnetic field B is the tesla (T) and of the area A is (
). So 1 Wb=1 T.m².
For a flat surface S of area A in a uniform magnetic field B, with 
being the angle between the vector normal to the surface S and the direction of the magnetic field B, we define the magnetic flux through the surface as:
We are told the values of and B, then we can calculate the magnitude
Explanation:
It is given that,
Force applied to object, 
Position, 
(b) The cross product of force and position vector is used to find the net torque about the z axis. It is given by :
or
The torque is acting in -z axis.
(a) The magnitude of torque is given by :
Hence, this is the required solution.
Answer:
Explanation:
Given
Two projectile is fired vertically upward
One has 4 times the mass of other
When Projectile is fired their trajectory is independent of mass of object. Also if they launched with same speed then both achieved same maximum height in same time and will hit the ground at the same moment.
Explanation:
Given that,
Wavelength of the light, 
Work function of sodium, 
The kinetic energy of the ejected electron in terms of work function is given by :
The formula of kinetic energy is given by :
Hence, this is the required solution.
Answer:
Given:
Thermal Kinetic Energy of an electron, 
= Boltzmann's constant
Temperature, T = 1800 K
Solution:
Now, to calculate the de-Broglie wavelength of the electron, 
:
(1)
where
h = Planck's constant = 
= momentum of an electron
= velocity of an electron
= mass of electon
Now,
Kinetic energy of an electron = thermal kinetic energy
(2)
Using eqn (2) in (1):
Now, to calculate the de-Broglie wavelength of proton, :
(3)
where
= mass of proton
= velocity of an proton
Now,
Kinetic energy of a proton = thermal kinetic energy
(4)
Using eqn (4) in (3):
