Given that metal cases of electrical appliances are connected to the wire, let's select the statement which is not correct from the list of statements.
The earth wire is used to protect you and help reduce the risk of receiving an electric shock. The earth wire reduces the risk of electric shock by creating a path for a fault or lose current to flow to the Earth.
The Live wire may become loose and touch the metal case. In this case, the earth wire will channel the fault current to the earth thereby reducing the risk of electric shock.
If the metal case becomes live, the earth wire conducts current to the ground. This helps prevent electric shock from the metal case.
The Earth wire has low or no resistance. It is always made of copper.
It provides a low resistance path to the ground.
Therefore, the statement ''the earth wire needs to have high resistance'' is NOT current.
ANSWER:
C. The earth wire needs to have a high reistance.
Using the Fundamental Equation of Wave, we have:
Letter B
Light that enters the new medium <em>perpendicular to the surface</em> keeps sailing straight through the new medium unrefracted (in the same direction).
Perpendicular to the surface is the "normal" to the surface. So the angle of incidence (angle between the laser and the normal) is zero, and the law of refraction (just like the law of reflection) predicts an angle of zero between the normal and the refracted (or the reflected) beam.
Moral of the story: If you want your laser to keep going in the same direction after it enters the water, or to bounce back in the same direction it came from when it hits the mirror, then shoot it <em>straight on</em> to the surface, perpendicular to it.
Answer:
λ = 1360 m
Explanation:
Given data:
frequency of driving nails is given as 1 stroke per second mean at every 0.25 sec she hit the nails
speed of sound is given as 340 m/s
we know that the wave equation is given as
Speed = frequency × wavelength,
v = f × λ
where,
v = speed in meters/second (m/s)
f = frequency in Hertz (Hz)
substituing value to get wavelength of her driving nails
λ = 1360 m
The speed is 0.2 meter per minute.
There is not enough information given in the question to determine the velocity.
