Tag: physics

Questions Related to physics

A force of 10 N of gravitational force in CGS units is  represented as

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. $10 Dynes$

  2. $10^2 Dynes$

  3. $10^5 Dynes$

  4. $10^6 Dynes$

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Correct Option: A
Explanation:

A force of 10 N of gravittional force in CGS units is represented by 10 Dynes.

Dyne is a CGS unit of force which accelerates a mass of one gram at the rate of one centimeter per second.

The presence of gravitational field is required for the heat transfer by

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. $conduction$

  2. $striring\ of\ liquids$

  3. $natural\ convection$

  4. $radiation$

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Correct Option: A
Explanation:

Presence of gravitational field is required for heat transfer by conduction.

The force experienced by a unit mass at a point in the gravitational field is called its

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. gravitational intensity

  2. electric intensity

  3. magnetic intensity

  4. gravitational constant

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Correct Option: A
Explanation:

The force experienced by a $unit $ mass at a point in the gravitational field $=F _g=mg=1\times g=g $ $ Newton $


We know that $g$ is called as gravitational intensity 

Hence correct answer is option $A $ 

The ratio of SI units to CGS of the gravitational intensity is

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. $10^3:1$

  2. infinity

  3. zero

  4. $10^2:1$

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Correct Option: D
Explanation:

Gravitational intensity is nothing but the acceleration due to gravity(g)

SI unit of g is $m/s^2=100cm/s^2$
But CGS unit of g is $cm/s^2$ 
So SI unit:CGS unit $=100:1$ 

Hence correct answer is option $D $ 

Which of the following represents the unit for gravitational intensity?

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. N

  2. $kgm^{-2}$

  3. $Nkg^{-1}$

  4. $ms^{-3}$

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Correct Option: C
Explanation:

Gravitational intensity is nothing but the acceleration due to gravity $=g=F _g/m$


Now we know that the SI unit of $F _g$ is $Newton(N) $ and that of $m$ is $kg$
So SI unit of $g=N/kg=Nkg^{-1}$ or $m/s^2$ 

Hence correct answer is option $C $ 

The space in which a body experiences a force by virtue of its mass, is called a/an

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. magnetic field

  2. electric field

  3. gravitational field

  4. none of these

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Correct Option: C
Explanation:

The region of space surrounding a body in which another body experiences a force of gravitational attraction is called a gravitational field.

The speed at which the gravitational field propagates is

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. Equal to the speed of light in vacuum

  2. Less than the speed of light in vacuum

  3. More than the speed of light in vacuum

  4. Either less or more than the speed of light in

    vacuum

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Correct Option: A
Explanation:

The speed of gravitational waves in the general theory of relativity is equal to the speed of light in vacuum.

The unit of (V) Gravitational Potential is

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. $\dfrac{\text{Joule}}{kg}$

  2. $\text{Joule}$

  3. $\dfrac{\text{Joule}}{s}$

  4. $\dfrac{kg}{\text{Joule}}$

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Correct Option: A
Explanation:

Gravitational potential is defined as the Gravitational energy per unit mass of the object on the planet. Unit of energy is always joule in SI units. Hence that of potential will be Joule/kg.

Value of gravitational constant, $'G'$ is

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. $6.674 08 \times 10^{-11} m^3 kg^{-1} s^{-2}$

  2. $4.674 08 \times 10^{-11} m^3 kg^{-1} s^{-2}$

  3. $6.674 08 \times 10^{11} m^3 kg^{-1} s^{-2}$

  4. $6.674 08 \times 10^{-11} m^3 kg^{-2} s^{2}$

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Correct Option: A
Explanation:

The value of G in SI units is $6.67408\times {10^{-11}}$

And the unit is $ Newton.metre^2/kg^2 $
Newton is $kg.m.s^{-2} $
Hence it becomes $ m^3.kg^{-1}.s^{-2} $

Gravitational field is 

physics gravitational fields representing a gravitational field gravitational field circular motion and gravitation

  1. directly proportional to square of the distance between two masses.

  2. inversely proportional to square of the distance between two masses.

  3. directly proportional to the distance between two masses.

  4. inversely proportional to the distance between two masses.

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Correct Option: B
Explanation:

The gravitational field is the region in which the gravitational force can be experienced or its presence can be felt. The intensity of gravitational field is the force acting on a unit mass of a body. 

Gravitational force is given by $Force = \dfrac{GMm} {R^2}$, 
where $G$ is gravitational constant, $M$ is the mass of the body which is creating the gravitational force, $m$ is the mass of the body which is undergoing gravitational force and $R$ is the distance between them. You can see that this force is inversely proportional to the square of the distance between the two masses. Gravitational field is given by gravitational force / mass of the 2nd body i.e. $m$. 
$Field = \dfrac{GM}{R^2}$. Hence it is inversely proportional to square of the distance between two masses.