Homework questions of Physics for Junior college (PUC, ISc, XII, CBSE, ICSE) Reply

Question 3

Deuteron is a bound state of a neutron (n) and a proton (p) with a binding energy BE = 2.2 MeV. A g-ray of energy E is aimed at a deuteron nucleus to try to break it into a neutron and proton so that n and p move in direction of incident g ray. If E = B.E. show that this is not possible. How much should BE be so that such a process can occur.

Question 4

Total charge –Q is uniformly distributed along length of a ring of radius R. A small test charge = q of mass m is kept at center of ring and is given a gentle push along the axis of the ring. More…

Physics for XII, ICSE. Preparatory Test for Quarterly. Reply

15. Describe the Rutherford atomic model by explaining results of Geiger Marsden scattering experiment. Draw a PE, KE, E diagram of a Rutherford H-atom. Draw the Marsden scattering experiment plot and Gold-foil alpha-particle deflection diagram and explain each with 1 or 2 sentences. What are the drawbacks of this model? (2 is enough)

16. Use the Bohr’s n-th level energy -13.61/n2 eV to find the energy of absorption from n=2 to n =6 state and energy of emission from n=5 to n=3 state.

17. Describe the Van-de-Graf generator, its principle, working and use. More…

Class XII, CBSE exam questions, Physics, Preparatory for Quarterly Exam. Reply

1. Where would Coulomb’s interaction be weaker in dielectric medium or vacuum?

2. Between dipole and a point charge whose Electric Potential reduces faster?

3. What is the work done when a charge makes a rectangular path on an equi-potential surface?

4. Write the de-Broglie formula for wavelength of a wave-particle if its momentum is p?

5. Define refractive index from angle of incidence and angle of reflection. More…

Class XII, CBSE exam questions, Physics, Updated Version 2 Reply

6. State how density of electric lines of force is related to the Electric Field Vector intensity E. Also mention another three properties of the lines of forces.

7. Write the vector expression for Coulomb’s law and state 3 forces that are conservative forces by nature.

8. How one defines the direction of a Dipole Vector? Define a unit dipole vector p. Write the expression for dipole vector by using p and the magnitude of charge = 3 Q and separation between the charge as 1 Angstrom.

9. What’s the energy of an alpha particle if we place it in a potential difference of 100 Volt assuming its at rest at this location? What will be the energy of a proton if its placed at the same location at rest. More…

Class XII, ICSE exam questions, Physics, Updated Version 2 Reply

Question 6 [2+3+2]

Obtain an expression for the Nuclear Size of an atom by solving for distance of closest approach (r) which is also known as Impact Parameter (say l). Use an incoming alpha-particle of mass mα and charge q that’s deflected by the presence of a nucleus of atomic number Z to obtain l. Now replace the variables by some numerical: mα = 6.8×10-27kg, e = 1.6 x 10-19 coul, Z=14, and vα= 2.0×107 m/s. Express the answer in Femto-meters.

Question 7 [3+4]

A proton has a radius R and the charge Q is uniformly distributed. Use Bohr’s atomic energy level formula for the 1st excited state {n=2} energy of the Hydrogen-atom. More…

Class XII, CBSE exam questions, Physics Reply

Electrostatics

6. State how density of electric lines of force is related to the Electric Field Vector intensity E. Also mention another three properties of the lines of forces.

7. Write the vector expression for Coulomb’s law and state 3 forces that are conservative forces by nature.

8. What happens to the charge on a conducting shell? What happens to lines of forces when a conducting shell is present in the path of the lines of forces? More…