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Long Answer Type Questions
Q. 1. (a) What are the drawbacks of Rutherford’s atomic model ? (b) What are the postulates of Bohr’s atomic model ?
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Q. 2. (a) What is radioactivity ? What is the difference between natural and induced radioactivities ?
(b) What is the law of radioactive disintegration 7 Hence define disintegration constant.
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Q. 3. What is meant by Alpha decay ? Estimate the velocity or kinetic energy of α-particle .
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Q. 4. Discuss the discovery of the neutrons .
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Related CBSE Information
[Short/Very Short Answer Questions-1, 2 Marks]
1. Name the series of hydrogen spectrum lying in ultraviolet region.
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2. The total energy of an electron in the first excited state of the hydrogen atom is about —3.4eV. What is the P.E. of the electron in this state ?
Answer
3. What is Bohr's quantisation condition for angular momentum of an electron in the second orbit ?
Answer
4. What is a-particle ? In the reaction zXA = a + Y, give the atomic number and mass number ofY.
Answer
5. What is beta decay ? Give one
[Short/Very Short Questions-1-2 Marks)
1. Intensity of incident radiation on a metal is doubled, what happens to kinetic energy of electrons
emitted ?
Answer
2. Calculate de Broglie wavelength of a body of mass 3 kg moving at 5 ms-1
Answer
3. What is the main features of a metal used for photoelectric emission ?
Answer
4. Why de-Broglie wavelength of a mass on the earth is not noticeable ?
Answer
5. The de-Broglie wavelength of a photon and an electron are the same. Which of the two has greater energy ?
Answer
6. What happens to the velocity of the
Q. 1. Mention two defects of a simple cell.
Answer
Q. 2. When are the voltage and current in a LCR series A.C. circuit in phase?
Answer
Q. 3. Why cannot two magnetic lines of forces due to a bar magnet cross each other? .
Answer
Q. 4. The magnetic flux threading a coil changes from 12 X 10-3 Wb to 7 X 10-3 Wb in 0.01 s. Calculate the induced e.m.f.
Answer
Q. 5. What are comets composed
(Short/V. Short Questions i.e. 1-2 Marks Questions)
1. Which direction would a compass point to if located right on the geometric north and south pole?
Answer
2. Define neutral point. Write the positions of N.P. when a small bar magnet is placed with its north pole (i) towards north of the earth, (ii) towards south of the earth.
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3. What is the value of angle of dip at a place situated on the magnetic equator of the earth ?
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4. Define the term magnetic moment.
Answer
5. Draw a diagram showing
Short/V. Short Questions i.e. 1-2 Marks Questions
1. Name two basic properties of electric charge.
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2. The electric potential at 0 - 9 m from a point charge is + 50 V. Find the magnitude and nature of the charge.
Answer :
3. Small ozone layer on the top of atmosphere is crucial for human survival. Why ?
Answer :
4. Sketch lines of force due to point charges (i) q < 0 ; (ii) q > 0.
Answer :
5. Define dielectric constant in terms of capacitance of a