Tag: physics

Questions Related to physics

Fill in the blank spaces by choosing the correct words from the options given below.

The hulls of the______are made very strong to withstand huge pressure exerted by the sea water. 

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. $liquids$

  2. $gases$

  3. $submarines$

  4. All of the above

Show answer
Correct Option: C
Explanation:

Submarines.
The hull of Submarines are specially Strengthened to prevent it from collapsing from the high pressure of the water outside while submerged. Roughly every $30$ feet of depth under water adds another atmosphere of inward pressure on the hull.

A deep sea diver may hurt his ear drum during diving because of:

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. lack of oxygen

  2. more atm pressure

  3. more water pressure

  4. all of the above

Show answer
Correct Option: C
Explanation:

The pressure at a depth $h$ below the surface of water is given by 

$P=P _0+h\rho g$
Hence as the depth increases, the pressure increases.
Due to this increased pressure, as the diver goes deeper in sea water, the ear drum may get damaged.

In cities water supply from an overhead tank to.the houses is done due to:

physics pressure pressure in fluids pressure in liquids introduction to pressure

  1. difference in pressure

  2. gravitational force

  3. decrease of friction in pipes

  4. flow of liquid

Show answer
Correct Option: B
Explanation:

The water in an overhead tank has higher gravitational potential to compared to water which finally flows out of the taps in the houses. 
The water moves due to this decrease in gravitational potential energy of water by flowing out of taps, or, the water is supplied by the gravitational force acting on water.

Fluids include

a) Solids    
b) Liquids  
c) Gases

physics force and pressure pressure in fluids pressure in liquids introduction to pressure

  1. a and b

  2. b and c

  3. a and c

  4. All the above

Show answer
Correct Option: B
Explanation:

A fluid is a substance that has no fixed shape and yields easily to external pressure; a gas or  a liquid, or, which can easily flow.

It is due to this property of variation of pressure along a fluid that it exerts a buoyant force on a body placed inside it. 

What is the difference between the pressure on the water surface and that on the bottom?

physics force and pressure pressure in fluids pressure in liquids introduction to pressure

  1. $\rho gh$

  2. $\frac{\rho g}{h}$

  3. Zero

  4. Infinity

Show answer
Correct Option: A
Explanation:

The pressure at the bottom of the water surface is

$P=\dfrac{F}{A}=\dfrac{W}{A}=\dfrac{Ah\rho g}{A}=\rho gh$

A gold coin has a charge of $+10^{-4} C$. The number of electrons removed from it is:

physics static electricity properties of charges charge properties of charge

  1. $10^6$

  2. $625 \times 10^{12}$

  3. $1.6 \times 10^{-25}$

  4. $1.6 \times 10^{13}$

Show answer
Correct Option: B
Explanation:

The total charge of electrons removed from the coin would be equal to the positive charge acquired by the coin.

Thus, $10^{-4}C=n\times 1.6\times 10^{-19}C$
$\implies n=625\times 10^{12}$

Q(charge)= ?

physics electric current, potential difference and resistance properties of charges charge properties of charge

  1. $\displaystyle n/e$

  2. $\displaystyle ne$

  3. $\displaystyle e/n$

  4. All

Show answer
Correct Option: B
Explanation:

Q=ne, according to Quantum nature of charge, in nature charge always occurs as an integer multiple of electronic charge i.e. $\displaystyle Q=\pm ne$

A parallel late condenser consists of two circular plate each of radius $8cm$ separated by a distance of $2mm$. It is charged by an external source, with a constant charging current of $0.15$ A. The displacement.curcent is

physics static electricity properties of charges charge properties of charge

  1. $0.10A$

  2. $0.15A$

  3. $0.20A$

  4. $0.30A$

Show answer
Correct Option: A

Choose best option about cavity for a charged metallic sphere: 

physics static electricity properties of charges charge properties of charge

  1. Net field inside the cavity is zero

  2. Net field inside the metal is non-zero constant

  3. Potential inside the metal is constant

  4. Potential outside metal is constant

Show answer
Correct Option: A
Explanation:

Inside the cavity of charged measure sphere net electric field is non zero constant.

$\therefore $ Option $A$ is correct.

Two charges 2$\mathrm { uC }$ and 1$\mathrm { \mu }C$ are placed at adistance of 10$\mathrm { cm }$ . The position of the third charge from2$\mu \mathrm { C }$ between them so that it does not experience any force

physics static electricity properties of charges charge properties of charge

  1. $7cm$

  2. $2cm$

  3. $5.858cm$

  4. $8cm$

Show answer
Correct Option: C