Answer:
1200m/s
Explanation:
initial velocity=72km/h=20m/s
Final velocity=40m/s
Distance=0.5m
Now,
2as=v^2-u^2
or,2*a*0.5=40^2-20^2
or,1a=1200
or,a=1200/1
therefore,acceleration=1200m/s
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Answer:
D. A low lambda, λ, and a high nu, ν
Explanation:
- Both x-rays and radio waves are electromagnetic waves that are part of the electromagnetic spectrum.
- <em><u>Radio waves have the longest wavelengths in the electromagnetic spectrum and the lowest frequency.</u></em>
- X-rays on the other hand <em><u>have a higher frequency compared to radio waves and a lower wavelength than that of the radio waves</u></em>.
- All electromagnetic waves in the electromagnetic waves travel with a speed of light, 3.0 × 10^8 m/s. They also posses energy given by the formula E = hf, where h is the plank's constant.
Answer:
The maximum current which can flow through a fuse without melting it, is called its rating. ... If current higher than 8 A flows through the fuse, it would melt and circuit gets broken. ... Hence, fuse acts as a safety device
Answer: a) -3.5m b) 0.22man
Explanation:
a) A near sighted person is a person that can only see near objects clearly but not far objects.
According to the lens formula
1/u+1/v = 1/f
where u = object distance (distance between the object and the lens)
v = image distance (distance between the image and the lens)
f = focal length of the lens
Given u= infinity v = 3.5m f= ?
1/f = 1/infinity +1/3.5
Since the lens used for correcting near sighted person is concave lens therefore the image distance is negative due to virtual image produced by the lens.
We then have 1/f1 = 1/infinity -1/3.5
f1 = -3.5m
b) A far sighted person is a person that can only see far objects clearly but not near objects.
According to the lens formula
1/u+1/v = 1/f
Given u= 0.35m v = 0.6m f2= ?
1/f2 = 1/0.35 + 1/0.6
Since the lens used for correcting far sighted person is convex lens therefore the image distance is positive due to mostly real image produced by the lens (reason why the image distance is positive.
f2 = 0.22m
Answer: 1. B. The number of electrons emitted from the metal per second increases.
2. The maximum speed of the emitted electrons increases.
The stopping potential increases
Explanation:
Photoelectric effect is simply referred to as the emission of electrons that occurs when there's an electromagnetic radiation. An example of such electromagnetic radiation is when material is being hit by light.
Assuming that the light incident on the metal surface causes electrons to be ejected from the metal, the number of electrons emitted from the metal per second increases if the intensity of the incident light is increased.
Also, if the initial light incident on the metal surface causes electrons to be ejected from the metal, the maximum speed of the emitted electrons increases and the stopping potential increases.
