Not at all. Density on its own is not sufficient
Answer:
A). 1.9 cm
Explanation:
m = Mass of brick = 12 kg
g = Acceleration due to gravity = 9.81 m/s²
r = Radius of hose
A = Area = 
F = Force = 
Let us assume that the pressure required to lift the brick would be atmospheric pressure

The radius of the hose should be 1.9 cm
Answer: B. meteorites, UV rays
The earth's atmosphere plays an important role in shielding the space rocks and meteorites enters inside the earth due to collision with the celestial body. Due to high heat and pressure in the mesospheric layer of the atmosphere these meteorites burned up before reaching the biosphere or hydrosphere system of the earth. The UV rays are protected from entering into the earth atmosphere by the ozone layer present in the stratosphere of the atmosphere. Both meteorites and UV rays can negatively effect the human population. Therefore, the atmosphere is an agent which provides protection against them.
Answer:
B)
Explanation:
Negative (-) charge M will not move towards negative (-) charge K because, same charges will not attract each other in the given case
Negative (-) charge at the M tends to move towards positive (+) charge L in the direction of B) because opposite charges attract each other.