Four Fundamental Forces

Q. The magnitude of electric field intensity $E$ is such that an electron placed in it would experience an electrical force equal to its weight is given by
(Mass of $e^{–}=m$)

1. $mge$
2. $\frac{mg}{e}$
3. $\frac{e}{mg}$
4. $\frac{e^2}{m^2}g$

Q.

Why is gravity at the center of earth zero?

Q. If mass of the electron $=9.1\times {10}^{-31}\text{kg}$, charge on the electron $=1.6\times {10}^{-19}\text{C}$ and $g=9.8{\text{ms}}^{-2}$. Then, the intensity of the electric field required to balance the weight of an electron is -

1. $5.6\times {10}^{-9}\text{N/C}$
2. $5.6\times {10}^{-11}\text{N/C}$
3. $5.6\times {10}^{-8}\text{N/C}$
4. $5.6\times {10}^{-7}\text{N/C}$

Q.

Why is the binding energy constant between 30 and 170?

Q. Two charged particles having masses in the ratio $2:3$ and charges in the ratio $1:2$ are released from rest in a unifrom electric field. After $1$ minute, the their $K.E$ will be in the ratio of

1. $1:3$
2. $2:5$
3. $3:8$
4. $3:4$

Q. A positively charged ball hangs from a silk thread. We put a positive test charge $q_0$ at a point and measure $\frac{F}{q_0}$, then it can be predicted that the electric field strength E.

1. Cannot be estimated
2. $>\frac{F}{q_0}$
3. $=\frac{F}{q_0}$
4. $<\frac{F}{q_0}$

Q.

If a proton and anti-proton come close to each other and annihilate, how much energy will be released?

Q.

Why is intermolecular forces are electromagnetic in nature?

Q.

The atmosphere is held to the earth by ______________.

Q.

State any three effects of a force.

Q.

Define muscular force, electrostatic force, and gravitational force. Give one example of each.

Q.

Two particles of charges Q₁ and Q₂ placed at a some distance the force between them is f if the distance between them is reduced to half and charge on each particle is doubled the force between the particles would become?

Q. The sum of all electromagnetic forces between different particles of a system of charged particles is zero

1. only if all the particles are positively charged
2. only if all the particles are negatively charged
3. only if half the particles are positively charged and half are negatively charged
4. irrespective of the signs of the charges

Q.

Which type of force is exerted by electrostatic charge?

Q. 28. Two charged insulating spheres of radiusR are kept at a distance d (d> 2R). Onehas a charge + q and the other-q. The forcebetween them will be:221 q(B):0 d2(D) None of these4πε 29.Two charged conducting spheres of radius"R are kept at a distance d(d > 2R). One has a charge + q and theother +q. The force between them will be:2(B) Ao 2(D) None of these4τε o d4πε 02

Q. Which of the following is not an Electromagnetic force?

1. Reaction on a body
2. Tension in a string
3. Weight of a body
4. Elastic force in a spring

Q.

During dry weather, while combing hair, sometimes we experience hair flying apart. The force responsible for this is

1. force of gravity

2. electrostatic force

3. the force of friction

4. magnetic force

Q.

A magnet attracts an iron piece by __________an_____________ pole on its near end.

Q.

Sir is there anything called centre of charge ? Like centre of mass.

Q.

Can non- living objects exert force? If yes, give two examples.

Q. Let $E$, $G$ and $N$ represent the magnitudes of electromagnetic, gravitational and nuclear forces between two electrons at a given separation. Then

1. $E>N>G$
2. $G>N>E$
3. $N>E>G$
4. $E>G>N$

Q. (a) Write three characteristic properties of nuclear force.

(b) Draw a plot of potential energy of a pair of nucleons as a function of their separation. Write two important conclusions that can be drawn from the graph.

Q.

Explain the reason behind the animals falling during rain? Please give clear explain.

Q. When John Cena shook hands with Randy Orton, what kind of force did they exert?

1. Electromagnetic
2. Strong Nuclear
3. Gravitational
4. Weak Nuclear

Q.

How do you define gram force?

Q.

The person who has been awarded the title of the Father of Physics of 20 th century is (1) Madame curie (2) C V raman (3) Neils Bohr (4) Albert Einstein

Q. A neutral particle is at rest in a uniform magnetic field $\overrightarrow{B}$. At $t=0$, particle explodes into two particles, each of mass $m$ and one of them have charge $q$. Both of these move off in separate paths lying in plane perpendicular to $\overrightarrow{B}$. After time $t$, both particles collide, then $t$ will be:

1. $\frac{2\pi m}{qB}$
2. $\frac{\pi m}{qB}$
3. $\frac{\pi m}{4qB}$
4. $\frac{\pi m}{6qB}$

Q.

Pick the correct option - If all matter were made of electrically neutral particles such as neutrons,

1. there would be no force of friction

2. there would be no tension in the string.

3. it would not be possible to sit on a chair.

4. the earth would not move around the sun.

Q.

What is the key concept of quantum field theory?

Q. Compute the ratio of the gravitational force and electrostatic force between an electron (mass $9.1\times {10}^{31}kg$) and a proton (mass $1.7\times {10}^{-27}kg$)