Answer:
First, as you may know, the light travels at a given velocity.
In vaccum, this velocity is c = 3x10^8 m/s.
And we know that:
distance = velocity*time
Now, if some object (like a star ) is really far away, the light that comes from that star may take years to reach the Earth.
This means that the images that the astronomers see today, actually happened years and years ago (So the night sky is like a picture of the "past" of the universe)
Also, for example, if an astronomer sees some particular thing, he can apply a model (a "simplification" of some phenomena that is used to simplify it an explain it) and with the model, the scientist can infer the information of the given thing some time before it was seen.
Answer:
h = 3.1 cm
Explanation:
Given that,
The volume of a oil drop, V = 10 m
Radius, r = 10 m
We need to find the thickness of the film. The film is in the form of a cylinder whose volume is as follows :
So, the thickness of the film is equal to 3.1 cm.
Answer:
1. Attract
2. Repel
3. Attract
4 Repel
always remember when dealing with magnets, Opposites attract
Answer:
Balances and Scales
A balance compares an object with a known mass to the object in question. One example of a balance is the triple beam balance. The standard unit of measure for mass is based on the metric system and is typically denoted as kilograms or grams.
Answer:
Part a)
%
Part b)
%
Explanation:
As we know that total power used in the room is given as
here we have
Part a)
Since power supply is at 110 Volt so the current obtained from this supply is given as
now resistance of transmission line
now power loss in line is given as
Now percentage loss is given as
%
Part b)
now same power must have been supplied from the supply station at 110 kV, so we have
now power loss in line is given as
Now percentage loss is given as
%
