Answer: 134 neutrons are there in the nucleus of Radon-220
Explanation:
Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.
Thus, number of protons = atomic number = 86
Mass number is the number of the entities present in the nucleus which is the equal to the sum of the number of protons and electrons.
Mass number = Number of protons + Number of neutrons
220 = 86 + Number of neutrons
Number of neutrons = 134
Answer:
The correct option is b) In galaxy clusters
Explanation:
A type of galaxy that appear elliptical in shape and have an almost featureless and smooth image is known as the elliptical galaxy.
An elliptical galaxy is three dimensional and consists of more than one hundred trillion stars which are present in random orbits around the centre.
Elliptical galaxy is generally found in the galaxy clusters.
Answer:
The answer is 1/16
Explanation:
1. Persistence of vision refers to the optical illusion that occurs when visual perception of an object does not cease for some time after the rays of light proceeding from it have ceased to enter the eye. 2. The persistence of vision for normal eye is 1/16 if a second.
If you're using the bulb as a source of light, then it's. 14/60 = 23.3% efficient.
If you're using it to heat a bird nest or a hamster cage, then it's. 46/60 = 76.7% efficient !
It just depends on your point of view, and what you consider 'useful' output.