Answer:
(a) 2 (b) 4 (c) 4
Explanation:
Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
Rules for significant figures:
- Digits from 1 to 9 are always significant and have infinite number of significant figures.
- All non-zero numbers are always significant. For example: 654, 6.54 and 65.4 all have three significant figures.
- All zero’s between integers are always significant. For example: 5005, 5.005 and 50.05 all have four significant figures.
- All zero’s preceding the first integers are never significant. For example: 0.0078 has two significant figures.
- All zero’s after the decimal point are always significant. For example: 4.500, 45.00 and 450.0 all have four significant figures.
- All zeroes used solely for spacing the decimal point are not significant. For example : 8000 has one significant figure.
As per question,
0.000054 has 2 significant figures.
3.001 x 10⁵ has 4 significant figures.
5.600 has 4 significant figures.
Explanation:
The liquid contains only one element. -The liquid is a pure substance. The number at the end of an isotope's name is the -mass number. While looking at xenon (Xe) on the periodic table, a student needs to find an element with a smaller atomic mass in the same group.
A milliliter, because it is a smaller unit of measurement more fitting for a drop of water.
Answer:

Explanation:
It is given that, a proton moves at constant velocity, through a region in which there is an electric field and a magnetic field such that,
The electric field is, E = 800 V/m
Magnetic field, B = 0.25 T
We know that the net force in the region of magnetic and electric field is given by Lorentz forces. But here, the proton moves with constant velocity. So, the net force acting on it is 0.
i.e.

Hence, this is the required solution.
Scientists have designed solar cells to trap solar energy and convert it to D electrical energy. Its D because converting something has to do with recharging something and electronics have to charge. I hope I helped.