Relatively hot objects emit visible light.
Some examples:
==> the wire coils in the toaster;
==> the spoon that you stuck in the flame on the stove;
==> the fine wire in the lightbulb when current goes through it.
VERY radioactive objects also do that. But if you're actually
standing there watching an object that's THAT radioactive,
then you're in big trouble.
Answer:
a)
= 3,375 cm
, b) f₀ = 77.625 cm
Explanation:
The magnification of a telescope is, to see at the far point of vision (infinity image)
m = - f₀ / 
The length of the tube is
L = f₀ + 
a) The focal length of the eyepiece
L = - m
+ 
L =
(1-m)
= L / (1-m)
Let's calculate
= 81.0 / (1 - (-23.0)
= 3,375 cm
b) the focal length of the target
f₀ = -m
f₀ = 23 (3.68)
f₀ = 77.625 cm
In a cup of water it is a positive and negative charge of zero
Answer:
Ep = 3924 [J]
Explanation:
To calculate this value we must use the definition of potential energy which tells us that it is the product of mass by the acceleration of gravity by height.

where:
Ep = potential energy [J] (units of Joules)
m = mass = 40 [kg]
g = gravity acceleration = 9.81 [m/s²]
h = elevation = 10 [m]
![E_{p} =40*9.81*10\\E_{p} = 3924 [J]](https://tex.z-dn.net/?f=E_%7Bp%7D%20%3D40%2A9.81%2A10%5C%5CE_%7Bp%7D%20%3D%203924%20%5BJ%5D)
Answer:
The mass of moon is 1/100 times and its radius 1/4 times that of earth. As a result, the gravitational attraction on the moon is about one sixth when compared to earth. Hence, the weight of an object on the moon is 1/6th its weight on the earth.