Positive Rays and Sub Atomic Particles

Q.

What is meant by 'negative and positive charges are equal in magnitude , so the atom as a whoke is neutral' ?

Q.

When beryllium is bombarded with $\alpha$ - particles, extremely penetrating radiations which cannot be deflected by electrical or magnetic field are given out. These are

1. A beam of neutrons

2. X-rays

3. rays

4. A beam of protons

Q.

The mass of the electrons is negligible when compared to the mass of protons.

1. True

2. False

Q.

The charge on the neutron.

Q.

The charge of an electron is equal and opposite to the charge of a proton.

1. False

2. True

Q. An atom is electrically neutral. How can it be charged?

Q. The mass of an electron is negligible when compared to that of a proton.

1. True
2. False

Q.

The positive charge on the nucleus is due to the presence of ................ in it.

1. protons

2. neutrinos

3. neutrons

4. electrons

Q. What will be the electric charge of an atom if there are protons, neurons, electron?

Q. The mass number is the sum of number of protons and neutrons present in the nucleus of an atom.

1. False
2. True

Q.

____ is the fundamental particle that is not present in the nucleus of a hydrogen atom.

1. Electron

2. Proton

3. Nucleon

4. Neutron

Q.

If we bring a comb near some small pieces of paper, nothing happens but if we comb our hair and then bring this comb near the pieces of paper, it attracts the pieces of paper towards it. Why?

1. On rubbing two objects together, they become magnetic and start attracting each other

2. On rubbing two objects together, they become electrically charged

3. On rubbing two objects together, they attract each other

4. Small piecs of paper are light in weight so they are attracted towards comb

Q.

Atoms consists of protons, neutrons and electrons. If the mass of neutrons and electrons were made half and two times respectively to their actual masses, then the atomic mass of ${}_6{C}^{12}$

1. Will be reduced by 25%

2. Will remain approximately half

3. Will remain approximately the same

4. Will become approximately two times

Q. What is formal charge in detaior with an example

Q.

What is the charge of Mg in $Mg{Cl}_2$ ?

1. +1

2. +3

3. +2

4. +4

Q.

Proton has the charge of +1.6022 $\times$ ${10}^{-19}$C.

1. True

2. False

Q. What are canal rays? Explain briefly.
[2 Marks]

Q.

Select the correct statement(s) regarding the electrical charge of electrons and protons.

1. Electrons are positively charged.

2. Electrons are negatively charged.

3. Protons are positively charged.

4. Protons are negatively charged.

Q.

Who discovered the subatomic particle called neutron?

1. Rutherford
2. Ernst Goldstein
3. J.J Thomson
4. James Chadwick

Q.

Why did the discovery of neutrons came very late?

1. Neutrons are present in nucleus

2. Neutrons are highly unstable particles

3. Neutrons are charge less

4. Neutrons do not have

Q.

Charge on an electron is

1. $1.67\mathrm{x}{10}^{-16}\mathrm{C}$

2. $1.67\times {10}^{-17}\mathrm{C}$

3. $1.67\times {10}^{-18}\mathrm{C}$

4. $1.67\times {10}^{-19}\mathrm{C}$