CBSE Class 12 Physics Question Paper 2020 Set B

CBSE Class 12 Physics Question Paper 2020 Set B. Students can download the last year board exams question papers using the link below. Free download of examination question papers with solutions. Last 10 year question papers should be practised to get better marks in examinations.

Section A

1. An electric field of 3Vcm^-1 across a cylindrical conductor produces a current of 1A cm^-2 .What will be its electrical conductivity?

2. Can two equipotential surfaces insect each other? Justify your answer.

3. A charged particle falls vertically downwards in a uniform magnetic field in the direction of north - south direction. What is the direction of magnetic force experienced by the charged particle?

4. Define magnetic flux and write its S.I. unit.

5. Write the units magnetic pole strength and dipole moment.

Section B

6. Derive the expression for magnetic dipole moment due to an electron revolving around nucleus in an atom.

7. The electric field intensity and potential at a point due to a point charge are 36 N/C and 18J/C respectively. Calculate magnitude and position of the charge from the point.

(OR)

Three point charges q, 2q and 3q are placed at the corners of an equilateral triangle of side 1m. Calculate the work required to move the charges to corners of small equilateral triangle of side 0.5m.

8. The true value of dip at a placed is 30^o. The vertical plane carrying the needle is turned through 45^ofrom the magnetic meridian. Calculate the apparent value of dip.

9. A 10 m rod is kept in east-west direction. It is falling at a speed of 5 m/s at a place where earth’s magnetic field B = 0.4 G and angle of dip is 0°. Calculate instantaneous potential difference at the end of the rod and mention which end is at higher potential.

10. The resistance of a tungsten filament at 150^oC is 133Ω. What will be its resistance at 500o? The temperature co efficient of resistance of tungsten is 0.0045^oC^-1

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