Answer:
LAW 1 : For a given metal and frequency, the number of photoelectrons emitted is directly proportional to the intensity of the incident radiation.
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LAW 2: For a given metal, there exists a certain frequency below which the photoelectric emission does not take place. This frequency is called threshold frequency.
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LAW 3: For a frequency greater than the threshold frequency, the kinetic energy of photoelectrons is dependent upon frequency or wavelength but not on the intensity of light.
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LAW 4: Photoelectric emission is an instantaneous process. The time lag between incidence of radiations and emission of electron is 10^-9 seconds.
Explanation:
The input work = Force x distance
So I/P = 45 x 1.5 = 67.5 N.m
The output work = Force x distance
So, O/P = 87.6 x 0.4 = 35.04 N.m
Efficiency = (output work / Inputwork) x 100
= ( 35.04/67.5) x100
Efficiency = 51.91 %
Answer:
C.Vacuum
Explanation:
There are three methods of transfer of heat:
1) Conduction: conduction is the transfer of heat by direct contact between the molecules of two objects (or two substances). The particles of the hotter object vibrate faster than the particles of the colder object, so energy is transferred by collisions of the molecules from the hotter object to the colder object.
2) Convection: convection is the transfer of heat by mass movement of molecules. This occurs in fluids (liquids or gases), when an external source of heat is applied to the fluid. As a result, the part of the fluid closer to the source gets warmer, so it becomes less dense and rises, while the colder part sinks and replaces the hotter part, forming a convective current. The process continues until the heat source is removed.
3) Radiation: radiation is the transfer of heat carried by electromagnetic waves. Electromagnetic waves can travel in any medium and in a vacuum, so they are the only type of heat transfer that can occur in a vacuum (while conduction and convection cannot occur in a vacuum).
Answer:
103.5m/5.5s= 18.8m/s
Explanation:
Formula for finding velocity average is:
v average= change in x(meters)/ change in time(seconds).
Answer:
Explanation:
The formula for the single-slit diffraction is
where
y is the distance of the n-minimum from the centre of the diffraction pattern
D is the distance of the screen from the slit
d is the width of the slit
is the wavelength of the light
In this problem,
, with n=2 (this is the distance of the 2nd-order minimum from the central maximum)
Solving the formula for d, we find:
