All of these things were seen in formal experiments by the 19th century. But some of them are easy to see in your own home. It's obvious that light can reflect - you just have to look in a mirror. Light bounces off the mirror and goes into your eye so you can see yourself. It's also obvious that light can refract: All you have to do is put a spoon in a large glass of water and watch how the spoon appears to bend.
That happens because the light is bending as it moves between air and water. Both of these things can be seen even more clearly in a laboratory using beams of light or lasers.
Explanation:
It is given that,
Length of the copper wire, l = 4.4 m
Diameter of copper wire, d = 1.3 mm = 0.0013 m
Radius of copper wire, r = 0.00065 m
The resistivity of the copper wire, 
We need to find the resistance of the copper wire. It is given by :


R =0.055 ohms
So, the resistance of the copper wire is 0.055 ohms. Hence, this is the required solution.
The component of waves must have same frequency and phase.
when the component of waves vibrate at the same rate and attain maximum point at the same time, reinforcement of the waves amplitude occur to cause a constructive interference.However, when the two waves are out of phase where one is at minimum when the other is at maximum a destructive interference happens.
Wavelength, because of how it lengths out from the rest.
Answer
correct answer is 3.10
Explanation:
in this question we have to multiply two numbers 1.003 and 3.09.
1.003 has 4 significant digits and 3.09 has 3 significant digits so answer must have 3 significant digits.

Hope it will help you