Answer:
4.71 eV
Explanation:
For an electromagnetic wave with wavelength
the energy of the photons in the wave is given by
where h is the Planck constant and c the speed of light. Therefore, this is the minimum energy that a photon should have in order to extract a photoelectron from the copper surface.
The work function of a metal is the minimum energy required by the incident light in order to extract photoelectrons from the metal's surface. Therefore, the work function corresponds to the energy we found previously. By converting it into electronvolts, we find:
Answer:
The magnifying power of this telescope is (-60).
Explanation:
Given that,
The focal length of the objective lens of an astronomical telescope, 
The focal length of the eyepiece lens of an astronomical telescope, 
To find,
The magnifying power of this telescope.
Solution,
The ratio of focal length of the objective lens to the focal length of the eyepiece lens is called magnifying of the lens. It is given by :
m = -60
So, the magnifying power of this telescope is 60. Therefore, this is the required solution.
Answer:
Explanation:
From the question we are told that
Velocity v=28m/s
Distance d=280
Generally the Newtons equation for motion is mathematically given as
Acceleration
Answer:
Volume of each grain of sand:
radius of the spherical grain is given,
The grains are made up of silicon dioxide.
The density is equal to 
Then, the mass of each grain is given by:
