CBSE Physics Sample Question Paper : Set-2
Q. 1. Define atomic mass unit (a.m.w.) write the energy equivalent of atomic mass unit in MeV.
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Q. 2. Why does the electrical field inside a dielectric decrease when it is placed in an external electric field?
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Q. 3. State any rule which relates the direction of electric current and the direction of the accompanying magnetic field.
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Q. 4. What is the phase difference between the voltage drop across L and C in a series LCR circuit connected to an a.c, source?
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Q. 5. Arrange the following radiations in the descending order of their wavelengths. Radio waves, X-rays, UV rays, Red light.
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Q. 6. A transistor is being used as a common emitter amplifier. What is the value of phase difference, if any, between the collector-emitter voltage and the input signal?
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Q. 7. Two wires A and B of the same material and having same length have their crosssectional areas in the ratio 1: 4. What would be the ratio of heat produced hi these wires when same voltage is applied across each?
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Q. 8. Why does the conductivity of a semiconductor increase with rise in temperature?
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Q. 9. Define the term critical angle for a given pair of media. Establish its relationship with their refractive index.
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Q. 10. Observations on a given device yielded-the following current-voltage data.
Current Voltage
(Ampere) (Volt)
1.0 19.7
2.0 39.4
3.0 59.1
Current (Ampere) Voltage
4.0
5.0 (Volt)
78.8
98.5
Draw V-I graph using the above data
What conclusion can you draw from the graph with regard to ohmic or non-ohmic nature of device?
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Q. 11. Suppose you have two bars of identical dimensions—one made of paramagnetic substance and the other of dia-magnetic substance. If you place these bars along a uniform magnetic field, show diagramatically, what modifications in the field pattern would take place.
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Q. 12. What are thermal neutrons? Why are neutrons considered as ideal particles for nuclear fission?
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Q. 13. Calculate the equivalent capacitance between the points A and B in the following combination.
Image 
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Q. 14. A wire of resistance 4R is bent in the form of a circle. What is the effective resistance between the ends of diameter?
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Q. 15. A magnetised needle in a uniform magnetic Held experience a torque but no net force. However an iron nail near a bar magnet experien¬ces a force of attraction in addition to a torque. Explain.
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Q. 16. Figure below shows an inductor L and a resistor R connected in parallel to a battery through a switch. The resistance of R is the same as that of the coil that makes L. Two identical bulbs are put in each arm of the circuit
(i) which of the bulbs lights up earlier when S is closed ?
(it) will the bulbs be equally bright after some time ?
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Q. 17. A convex lens made up of a material of refractive index µ1 is immersed in a medium of refractive index µ2. Trace the path of a parallel beam of light passing through the lens when
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Q. 18. The wave length of the second line of the Banner series in the Hydrogen spectrum is 4861 A. Calculate the wavelength of the first line.
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Q. 19. With the help of a circuit diagram explain how can you find the internal resistance of a primary ceil? Derive the necessary formula used.
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Q. 20. Draw the logic symbol and the truth table of an OR gate. Describe its realisation with circuit diagram using semi-conductor diode.
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Q. 21. (a) State and explain Huygen’s principle.
(b) Name the type of wave front that corresponds to a beam of light
(i) coming from a very far-off source
(ii) diverging radially from a point source.
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Q. 22. How will you determine the temperature of the sun? Derive the necessary formula used.
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Q. 23. A student has two wires of iron and copper of equal length and diameter. He first joins the two wires in series and passes electric current through the combination which increases gradually. After that he joins the two wires in parallel and repeats the process of passing current. Which wire will glow first in each case and why?
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Q. 24. A sunshine recorder globe of 30 cm diameter is made of glass of refractive index µ=1.5. A ray enters the globe parallel to the axis. Find the position from the centre of the sphere where the ray crosses the axis.
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Q.25. Differentiate between n-type and p-type semiconductors on the basis of energy band diagrams. Explain the process of conduction in both type of materials.
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Q. 26. The frequency of a cyclotron oscillator is 107 Hz. What should be the operating magnetic field for accelerating protons? If the radius of the dees of the cyclotron is 6 x 10-1 m. Calculate the energy of the proton beam produced by it in MeV. (e = 1.6 x 10-19 C, mp = 1.67 x 10-27 kg;
1 MeV = 1.602 X I0-13 joule.)
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Q. 27. A narrow monochromatic beam of light of intensity / is incident on a glass plate. Another identical glass plate is kept close to the first one and parallel to it. Each plate reflects 25 % of the incident tight and transmits the remaining. Calculate the ratio of minimum and maximum intensity hi the interference pattern formed by two beam obtained after reflection from each plate.
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Q. 28. With the help of a labelled diagram explain the principle, construction and working of an a.c. generator.
With the help of a labelled diagram explain the principle, construction and working of a step up transformer. Why is the core laminated?
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Q. 29. A glass rod rubbed with silk is brought close to two uncharged spheres in contact with each other inducing charge on them as shown in figure. Show with diagrams in each case what happens when
(i) The spheres are slightly separated?
(ii) The glass rod is subsequently removed?
(iii) The spheres are separated far apart?
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Q. 30. A photon of wavelength 3310 A falls on a photo cathode and an electron of energy 3 X 10-19 joule is ejected. If the wavelength of the incidence photon is changed to 5000 A, the energy of the ejected electron is 9.71 x 10-20 joule. Calculate the value of Plank’s constant and threshold wavelength of the photon.
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