Answer:
1. Letter A indicates the crest.
2. Letter E indicates the wavelength.
3. Letter C indicates the trough.
Explanation:
1. Determination of the the crest.
A crest is simply defined as a point on a wave where the displacement is maximum (i.e highest).
Considering the diagram given above, the point where the displacement is maximum is A. Therefore, A is the crest of the wave.
2. Determination of the wavelength.
The wavelength of a wave is simply defined as the distance between two successive crest or trough.
Obeserving the diagram above, we can see that E gives the distance between two successive crest. Therefore, E is the wavelength of the wave.
3. Determination of the trough.
A trough is simply defined as a point on a wave where the displacement is minimum (i.e lowest). Thus we can say that the trough is the opposite of the crest.
Considering the diagram given above, the point where the displacement is minimum is C. Therefore, C is the trough of the wave.
Radiation can pass through any phase of matter.
Examples:
Light, radio, heat, and X-rays, all pass through glass (solid),
water (liquid), and air (gas) very easily.
(Moreover, I would be remiss if I failed to point out in addition that
microwave radiation passes through meatloaf and coffee with only
partial attenuation due to absorption.)
Answer:
(d) 2.93 x 10⁻³ N
Explanation:
Given;
current in the wire, I = 11.4 A
angle of inclination, θ = 11.4⁰
magnetic field on the wire, B = 11. 4 x 10⁻³
length of the wire, L = 11.4 cm = 0.114 m
The magnitude of magnetic force on the wire is given by;
F = BILsinθ
F = (11.4 x 10⁻³)(11.4)(0.114)(sin 11.4°)
F = 0.00293 N
F = 2.93 x 10⁻³ N
Therefore, the correct option is "D"
Answer:
Less gravity and Vacuum
Explanation:
As per the laws of gravity, acceleration due to gravity is independent of mass of an object. That means if you drop two objects of different mass form same height with zero initial speed, they will reach the ground at the same time.
Galileo had given this theory and proved it. But when you take one object as feather the presence of air makes it float and the law seems to fail. The law is correct but the only reason it fails is because the feather starts floating in the air.
To prove this we need a vacuum chamber with a great height to witness the free fall condition. Creating such a chamber on Earth is very difficult. David Scott had these advantages on the Moon. As Moon doesn't have any atmosphere so he got a natural vacuum environment.
Also, as the acceleration due to gravity on Moon is of that on the Earth, it will take less time to touch the surface and one can easily observe the free fall without any aid of high speed camera.