Out of the given options, ‘it is described as a fundamental force and therefore does not depend on other forces’ is the true statement about gravity.
Answer: Option B
<u>Explanation:
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As we all know that there are four fundamental forces existing in the universe- Electromagnetic force, strong forces, weak forces and the gravitational force.
These are the forces that don’t depend on any other physical force to draw a considerable impact on the physical objects. The gravitational force can be defined as,
Where,
G = Gravitational Constant
= Masses of two substances under consideration
R = distance between the two substances.
Looking upon the formula of gravitational force we can easily estimate that the gravitational force relies on the mass of substances and the relative distance between them. There is no factor than the air friction that hinders the gravitational force and that too in a negligible amount.
Answer:
I think the answer is
C) iron nails are attracted towards all materials
Answer: False
Explanation:
Relative to the concept of radiations, a black body is an object capable of absorbing any form of electromagnetic radiation irrespective of its frequency or angle of incidence when incident on such object.
However, the same cannot be said about real bodies as real bodies are those which reflect all rays incident on them completely and uniformly in all directions.
One very important characteristic of black bodies is that they are ideal emmiters.
The concept of emmisivity is brought about by the existence of real bodies .
This is due to the fact that they are only able to emit radiation at a fraction of the black body energy levels.
Please note that by convention, the emmisivity of a real body is always less thaan 1.
As such they are not able to emit as much radiation as a black body at the same temperature.
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:
Answer:
0.96 m, upward
Explanation:
Initial velocity, u=0
Where 
Substitute the values
Hence,the block moves upward because displacement is positive.
