Answer:
The value is 
Explanation:
From the question we are told that
The weight of the block is 
The dimension of the block is 
Generally two atmosphere is equivalent to

Generally 1 atm = 
The area of the block would be evaluated using width and height because we need for the smaller surface to be in contact with the ground in order to maximize the pressure and minimize number of blocks
So

=> 
Generally the force due to this blocks is mathematically represented as

Here N is the number of blocks
So

=> 
Answer:
c. may be accompanied by the sound of explosively expanding hot air, called thunder.
Explanation:
Lightning is a discharge which is due to the reaction between oppositely charged charges in the clouds, or between clouds base and the Earth surface.
The motion of the cloud causes charging of clouds by friction, thus the reaction between opposite charges (jumping of charges from one cloud to another) in the cloud can lead to lightning. Also, oftentimes the bottom of a cloud is negatively charged so that this is attracted to the positive charge on the earth surface. Thus leading to a discharge called lightning.
Thus in the given question, the appropriate option is C. This implies that, lightning may be accompanied by the sound of explosively expanding hot air, called thunder.
Answer:
(5g/cm³)*(10cm³) = 50g
Explanation:
This is just a conversion formula. Easy to find using dimensional analysis.
(5g/cm³)*(10cm³) = 50g
Answer:
2.7067 eV
Explanation:
h = Planck's constant = 
c = Speed of light = 
= Threshold wavelength = 459 nm
Work function is given by

Converting to eV


The work function W0 of this metal is 2.7067 eV
Answer:
80 angle of incidence=angle of reflection
Explanation: