Subject

Physics

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
Advertisement

 Multiple Choice QuestionsShort Answer Type

1. Define capacitor reactance. Write its S.I. units. 
4986 Views

2. What is the electric flux through a cube of side 1 cm which encloses an electric dipole? 
2873 Views

3.

Graph showing the variation of current versus voltage for a material GaAs is shown in the figure. Identify the region of

i) negative resistance

ii) where Ohm’s law is obeyed.    

                         
1878 Views

4. Use Kirchhoff’s rules to obtain conditions for the balance condition in a Wheatstone bridge.
6021 Views

Advertisement
Advertisement

5.

Name the parts of the electromagnetic spectrum which is

(a) suitable for radar systems used in aircraft navigation.

(b) used to treat muscular strain.

(c) used as a diagnostic tool in medicine.

 Write in brief, how these waves can be produced.     


a)  Microwaves are suitable for Radar system used in air navigation. They are produced by special vacuum tubes namely klystron valve or magnetron valve.

b) Infrared waves are used to treat muscular strain. These ways are produced by the vibration of atoms and molecules.

c) X-rays are used as diagnostic tool in medicine. X-rays are produced when high energy electrons are suddenly stopped on metal of high atomic number and by the radio-active decay of nucleus. 
2197 Views

Advertisement
6.

A cell of emf ‘E’ and internal resistance ‘r’ is connected across a variable load resistor R. Draw the plots of the terminal voltage V versus
(i) R and
(ii) the current I.

It is found that when R = 4 Ω , the current is 1 A and when R is increased to 9 Ω , the current reduces to 0.5 A. Find the values of the emf E and internal resistance r.
5271 Views

7.

Two capacitors of unknown capacitances C1  and C2  are connected first in series and then in parallel across a battery of 100 V. If the energy stored in the two combinations is 0.045 J and 0.25 J respectively, determine the value of C1  and C2. Also, calculate the charge on each capacitor in parallel combination.

4147 Views

8.

State the principle of working of a galvanometer.

A galvanometer of resistance G is converted into a voltmeter to measure upto V volts by connecting a resistance R1 in series with the coil. If a resistance R2  is connected in series with it, then it can measure upto V/2 volts. Find the resistance, in terms of R1 and R2, required to be connected to convert it into a voltmeter that can read upto 2 V. Also find the resistance G of the galvanometer in terms of R1 and R2
3152 Views

Advertisement
9.

An inductor L of inductance Xis connected in series with a bulb B and an ac source.

How would brightness of the bulb change when (i) number of turn in the inductor is reduced, (ii) an iron rod is inserted in the inductor and (iii) a capacitor of reactance XC = XL  is inserted in series in the circuit. Justify your answer in each case.   
1895 Views

10. A concave lens of refractive index 1.5 is immersed in a medium of refractive index 1.65. What is the nature of the lens ? 
2072 Views

Advertisement