Q.No.210: - Why electric current pass through conductors?

Q.No.210: - Why electric current pass through conductors?

Ans: - Because conductors have electrons that are loosely packed with nucleus and become a free electron after getting a small energy. These free electrons conduct electricity.

Q.No.209: - Define conductors.

Q.No.209: - Define conductors.

Ans: - A conductor is a material that easily conducts electrical current. Most metals are good conductors. The best conductors are single element materials such as copper, silver and gold etc.

Q.No. 208: - Why electric current does not conduct through insulators under normal conditions?

Q.No. 208: - Why electric current does not conduct through insulators under normal conditions?

Ans: - Because in insulators electrons orbiting around the nucleus are tightly bound. The free electrons in the insulator are very rare, so that’s why the electric current did not pass through the insulators.

Q.No.207: - Define electric current.

Q.No.207: - Define electric current.

Ans: - Flow of electric charge from high to low potential is called electric current

                                           I    =    Q/t

Where I represents current, Q for charge and t for time.

Q.No.206: - Define insulator.

Q.No.206: - Define insulator.

Ans: - An insulator is a material that does not conduct electrical current under normal conditions. Most good insulators are compounds rather than single element materials

Q.No.205: - When an atom becomes a positive ion and when it becomes a negative ion?

Q.No.205: - When an atom becomes a positive ion and when it becomes a negative ion?

Ans: - When an atom loses an electron then it becomes a positive ion and when an atom accepts an electron then it becomes a negative ion. 

Q.No.204: - How ionization takes place?

Q.No.204: - How ionization takes place?

Ans: - Ionization takes place by providing sufficient amount of energy to the atom. The electrons become excited and get more energy. When the energy of valence electron overcome the electrostatic force between nucleus and that electron then electron detach from nucleus and atom become a positive ion.

Q.No.203: - Define ionization.

Q.No.203: - Define ionization.

Ans: - The process of losing electron from valence shell is known as ionization

Q.No.202: - How the energy vary in different shell of atom.

Q.No.202: - How the energy vary in different shell of atom.

Ans: - Electron that are away from nucleus have higher energy while the electrons nearer the nucleus have low energy.

If the orbit with n=1 have energy E₁

If the orbit with n=2 have energy E₂

If the orbit with n=2 have energy E₃

If the orbit with n=2 have energy E₄

If the orbit with n=2 have energy E_n-1

If the orbit with n=2 have energy E_n

Then,

E₁<E₂<E₃<E₄<E_n-1 <E_n

Q.No.201: - Define valence shell.

Q.No.201: - Define valence shell.

Ans: - The outermost shell of an atom is called valence shell. It may be partially or completely filled with electrons, but it cannot be empty at all.

Q.No.200: - What information about the structure of the nitrogen atom can be obtained from its nuclide 714N? In what way atom in 714N is different from the atom in 716N?

Q.No.200: - What information about the structure of the nitrogen atom can be obtained from its nuclide ₇¹⁴N? In what way atom in ₇¹⁴N is different from the atom in ₇¹⁶N?

Ans: -  

             ₇¹⁴N (Nitrogen): -

          Number of electrons          =         7

          Number of protons             =         7

          Number of neutrons           =    mass no - atomic no

          Number of neutrons           =     14 -7 = 7

          ₇¹⁶N (Nitrogen Isotope)

          Number of electrons          =         7

          Number of protons             =         7

          Number of neutrons           =    mass no – atomic no

          Number of neutrons           =         16 – 7 = 9

Q.No.199: - Tritium, 13H is radioactive isotope of Hydrogen. It decays by emitting an electron. What is the daughter nucleus?

Q.No.199: - Tritium, ₁³H is radioactive isotope of Hydrogen. It decays by emitting an electron. What is the daughter nucleus?

Ans: - 

Q.No.198: - How much of a 1g sample of pure radioactive mater would be left after four half-lives?

Q.No.198: - How much of a 1g sample of pure radioactive mater would be left after four half-lives?

Ans: - Amount of sample of pure radioactive matter         =      1g

           After 1^st half life 1T_1/2                                                 =   1/2g=0.5g

           After 1^st half life 2T_1/2                                                 =   0.25g

           After 1^st half life 3T_1/2                                                 =    0.125g

           After 1^st half life 4T_1/2                                                 =    0.0625g

Q.No.197: - Which type of natural radioactivity leaves the number of protons and the number of neutrons in the nucleus unchanged?

Q.No.197: - Which type of natural radioactivity leaves the number of protons and the number of neutrons in the nucleus unchanged?

Ans: - If gamma ray emit from the excited nucleus then only energy of the nucleus releases but atomic number and atomic mass remain same.

Q.No.197: - How long would you likely have to wait to watch any sample of radioactive atoms completely decay?

Q.No.197: - How long would you likely have to wait to watch any sample of radioactive atoms completely decay?

Ans: - Theoretically it will take an infinite time to decay completely because it radioactivity follow the exponential law