biharboard.ac.in Class XII Physics Model Question Paper 2017 : Bihar School Examination Board

Organisation : Bihar School Examination Board (BSEB)
Class : XII
Paper: Physics
Document Type : Model Question Papers
Year : 2017

Website : http://www.biharboard.ac.in/model-question-papers/
Download Question Paper : https://www.pdfquestion.in/uploads/10287-PHYSICS.pdf

Physics Model Question Paper :

Question Nos. 1 to 11 are of short answer type. Each question carries 2 marks. 11 × 2 = 22
1. What do you mean by surface charge density and write its SI unit ?

Related : BSEB Class XII Chemistry Model Question Paper 2017 : www.pdfquestion.in/10272.html

2. The vertical component of earth’s magnetic field at a place is 3 times the horizontal component. What is the angle of dip at this place ?

3. Give two applications of ultra-violet waves.
4. State Ampere’s circuital law. Express it mathematically.

5. A wire of resistance 10 ??is stretched to double its length. What will be its new resistance ?
6. State Brewster’s law. Express it mathematically
7. Derive the expression for de-Broglie wavelength ?

8. The powers of two lenses are +12D and –2D. They are placed in contact coaxially. What will be the focal length of the combination ?
9. Write logic symbol (Boolean expression) and truth table of ‘AND’ gate ?
10. Write full form of ‘LASER’ and ‘MASER’ ?
11. If the maximum amplitude of the AM wave is 12V and the minimum amplitude of this wave is 4V, find the modulation index is percentage.

Long Questions :
Question Nos. 12 to 15 are of long answer type.

** Answer must be explanatory and in your own language.
** Each question carries 5 marks
12. With the help of mean and labelled diagram explain the working principle of a transformer. Mention different types of losses in a transformer ?
13. Explain Biot-Savart law. With its help derive an expression for the magnetic field at any print on the axis of a current carrying circula loop ?

14. What do you mean by Photoelectric effect ? State and derive Einstein’s Photoelectric equation ?
15. State and explain refraction through convex spherical surfaces.

Model Set-2 :
Section-II : (NON-OBJECTIVE TYPE QUESTIONS)
** Question Nos. 1 to 11 are of short answer type. Each question carries 2 marks. 11 × 2 = 22

Short Questions :
1. Define electric field intensity and write its SI unit with dimension also.
Ans : The electric field intensity due to a source charge at any point in its electric field is defined as the force experienced by a unit positive charge placed at that point.

2. What is the function of ‘moderator’ and ‘Controlling rods’ in a nuclear reactor ?
Ans :
** Function of moderator is nuclear reactor—
** It slows down the speed of neutrons to make them useful for further fission.
** Function on controlling rods is nuclear reactor—
** It absorbs the excess no. of neutrons which are produced in reactor.

3. Welders wear special goggles or face masks with glass windows to protect their eyes from electromagnetic radiations.Name the radiations and write the range of their wavelength.
Ans :
** ultraviolet rays.
** The wavelength of UV rays is 400 nm to 1 nm.

4. Define the activity of a given radioactive substance. Write its S.I. unit.
Ans.:
** The total decay rate of a radioactive sample is called the activity of the sample.
** The S.I. unit of activity is ‘becquerel’.

5. Calculate the capacitance of the capacitor C. The equivalent capacitance of a combination between P and Q is 30 mF.
Ans :
Capacitors C1, C2 and C3 are in parallel, so the equivalent capacitance of these capacitors are
C’ = C1 + C2 + C3
= 20 + 20 + 20

6. Why the core of a transformer is laminated ?
Ans :
The core of a transformer is laminated to reduce the energy loss due to eddy currents. Laminations break the path of eddy currents. The energy loss due to eddy current also results in unnecessary heating of the transformer which may be harmful for the winding of the transformer.

7. The radius of curvature of the forces of a double convex lens are 10 c.m. and 15 c.m. If focal length of the lens is 12 c.m., field the refractive index of the material of the lens.
Ans : Given that,
R1 = 10 c.m.
R2 = –15c.m.
f = 12 cm.

8. What is the lens of Presbyopia and Astingmatism ?
Ans :
Case of Presbyopia—It arises due to the gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens.

9. What do you mean by conductivity of a material ? Give its SI units.
Ans : .
Conductivity is the reciprocal of the resistivity. It can be expressed as— 1/P Its S.I. unit is siemen metre–1 (Sm–1) or ohm–1 m–1.

10. What is Photoelectric effect ? Write Einstein’s photoelectric equation.
Ans :
Photoelectric effect—Photoelectric effect is the phenomenon of emission of electrons from the surface of metal when exposed to the radiation of suitable frequency. Einstein’s photoelectric equation can be expressed as— 1/2Mv2=hv – hv0