Graph of Variation of G

Q.

If acceleration due to gravity on the surface of a planet is two times that on the surface of the earth and its radius is double that of earth then, escape velocity from the surface of that planet in comparison to earth will be

1. $2v_e$

2. $3v_e$

3. $4v_e$

4. None of these

Q.

In order to make the effective acceleration due to gravity equal to zero at the equator, the angular velocity of rotation of the earth about its axis should be ($g=10m{s}^{-2}$ and radius of earth is 6400 kms)

1. 

2. 

3. 

4. 

Q.

The mass of the body on the moon is $40kg$. What will be the weight of the same body on the earth?

1. $240kg$
2. $392kg$
3. $240N$
4. $392N$

Q.

The mass of the moon is $1/81$ of earths mass and its radius $1/4$ that of the earth. If the escape velocity from the earths surface is $11.2$ km/sec, its value for the moon will be.

1. $0.14$ kms^-1

2. $0.5$ kms^-1

3. $2.5$ kms^-1

4. $5.0$kms^-1

Q.

A man can jump to a height of $1.5m$ on a planet A what is the height he may be able to jump on another planet whose density and radius are respectively $one-quarter$ and $one-third$ that of planet A

Q. Which one of the following graphs represents correctly the variation of the gravitational field (I) with the distance (r) from the centre of a spherical shell of mass M and radius a

1. 
2. 
3. 
4. 

Q.

Acceleration due to gravity on moon is $\frac{1}{6}$ of the acceleration due to gravity on earth. If the ratio of densities of earth $\left({\rho }_m\right)$ and moon $\left({\rho }_e\right)$ is $\left(\frac{{\rho }_e}{{\rho }_m}\right)=\frac{5}{3}$ then radius of moon $R_m$ in terms of $R_e$ will be

1. 

2. 

3. 

4. 

Q.

A body weighs $500N$ on the surface of the earth. How much would it weigh halfway below the surface of the earth?

1. $125N$

2. $250N$

3. $500N$

4. $1000N$

Q. How much energy must a gamma ray photon have, if it is to materialize into a pair of electron and positron, with each particle having a $K.E$ of $1\text{MeV}$?

1. $0.5\text{MeV}$
2. $1.0\text{MeV}$
3. $2\text{MeV}$
4. $3.02\text{MeV}$

Q.

The mass and diameter of a planet have twice the value of the corresponding parameters of earth.
Acceleration due to gravity on the surface of the planet is

1. 

2. 

3. 

4. 

Q.

A small block of super dense material has a mass of $3\times {10}^{24}$ kg.it is situated at a height h (much smaller than the earth's radius) from where it falls on the earth's surface.Find its speed when its height from the earth's surface has reduced to $\frac{h}{2}$.The mass of the earth is $6\times {10}^{24}$ kg.

Q.

At what distance from the centre of earth, the value of acceleration due to gravity $g$will be half that of the surfaces ($R$ $=$ Radius of earth)

1. $2R$

2. $R$

3. $1.414R$

4. $0.414R$

Q.

How does the value of ‘g’ changes with height?

Q.

Assertion A: The escape velocities of planet are same. But $A$ and $B$ are of unequal masses.

Reason R: The product of their masses and radii must be same.$M_1{R}_1=M_2{R}_2$

In the light of the above statements, choose the most appropriate answer from the options given below:

1. Both A and R are correct but R is NOT the correct explanation of A

2. A is correct but R is not correct

3. Both A and R are correct and R is the correct explanation of A

4. A is not correct but R is correct

Q.

A simple pendulum is constructed by hanging a heavy ball by a 5.0 m long string. It undergoes small oscillations. (a) How many oscillations does it make per second ? (b) What will be the frequency if the system is taken on the moon where acceleration due to gravitation of the moon is $1.67m{s}^{-2}$?

Q. Which of the following Gaussian surface is not useful?

1. 
2. 
3. 
4. (a) and (b) both.

Q. What should be the angular speed with which the earth must rotate on its axis so that a person on the equator would weigh $\frac{3}{5}$th of weight measured without considering earth's rotation ? (Take $R$ as the equatorial radius and $g$ as acceleration due to gravity)

1. $\sqrt{\frac{2g}{5R}}$
2. $\sqrt{\frac{2g}{R}}$
3. $2\sqrt{\frac{g}{R}}$
4. $\sqrt{\frac{g}{R}}$

Q.

How a massless thing(photon) can exist?

Q. In the following four periods
(i) Time of revolution of a satellite just above the earth’s surface $\left(T_{st}\right)$
(ii) Period of oscillation of mass inside the tunnel bored along the diameter of the earth $\left(T_{ma}\right)$
(iii) Period of simple pendulum having a length equal to the earth’s radius in a uniform field of 9.8 N/k $\left(T_{sp}\right)$
(iv) Period of an infinite length simple pendulum in the earth’s real gravitational field $\left(T_{is}\right)$

1. 
2. 
3. 
4. 

Q. Why are the air molecules in our atmosphere not escaping into outer space?

Q. Consider two solid spheres of radii $R_1=1\text{m},R_2=2\text{m}$ and masses $m_1$ and $m_2$, respectively. The gravitational field due to sphere $1$ and $2$ are shown. The value of $\frac{m_1}{m_2}$ is:

1. $\frac{2}{3}$
2. $\frac{1}{6}$
3. $\frac{1}{2}$
4. $\frac{1}{3}$

Q.

Average density of the earth

1. does not depend on g
2. is a complex function of g
3. is directly proportional to g
4. is inversely proportional to g

Q.

The average distance between the earth and the sun is $1.5\times {10}^{11}m$. If the mass of sun is $2\times {10}^{30}kg$ and that of earth is $6\times {10}^{24}kg$, then the force of gravitation between them is:

1. $3.557\times {10}^{21}N$

2. $5.357\times {10}^{21}N$

3. $3.557\times {10}^{22}N$

4. none of the above

Q.

A stone is thrown vertically upwards from the top of a tower $64$ metres high according to the law $S=48t-16t^2$. The greatest height attained by the stone above the ground is

1. $36m$

2. $32m$

3. $100m$

4. $64m$

Q. Assertion :The difference in the value of acceleration due to gravity at pole and equator is proportional to square of angular velocity of earth. Reason: The value of acceleration due to gravity is minimum at the equator and maximum at the pole.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q.

What is the force of gravity acting on a point of mass of $1\mathrm{kg}$ released from the height of $1\mathrm{m}$ from the surface of the earth; the radius of the earth is equal to $6.4\times {10}^6\text{m}$ , mass of earth is equal to $6\times {10}^{24}\text{kg}$ ?

Q.

As we move at higher altitude, the value of $g$_____ .

Q.

The value of g on the surface of moon is_________

Q.

A body weighs $25kg$ on the surface of the Earth. If the mass of the Earth is $6.0\times {10}^{24}kg$, the radius of the Earth is $6.4\times {10}^{6}m$ and the universal gravitational constant is $6.7\times {10}^{-11}N{m}^2/k{g}^2$, calculate the force acting upon the body and the Earth?

Q. A simple pendulum has a time period $T_1$ when on the earth's surface and $T_2$ when taken to a height $R$ above the earth's surface, where $R$ is the radius of the earth. The value of $T_2/T_1$ is :

1. $1$
2. $\sqrt{2}$
3. $4$
4. $2$