Physics midterm, for class XII, for C.B.S.E. and State boards.

Physics midterm, for class XII

SUB: PHYSICS

TIME: 3.15 Hrs MAXIMUM MARKS: 90

GENERAL INSTRUCTIONS:

1. Draw relevant diagram, figure wherever necessary.

2. Numerical problems should be solved with the relevant formulas.

PART — A

I. Answer all the following questions, 1 mark each ( 1 × 10 = 10 )

Question 1

Which of the following drops faster?

A. An electric dipole’s electric field B. An electric dipole’s electric potential

C. A point charge’s electric field D. A point charge’s electric potential

Question 2

Which medium will have a stronger electrostatic force between 2 charges?

A. Medium with $\epsilon = 10$ B. Medium with $\epsilon = 100$

C. Medium with $\epsilon = 81$ D. Free space, $\epsilon = \epsilon_0$

Question 3

Pick only the correct one “between an $\alpha-{particle}$ and a proton”

A. The $\alpha-{particle}$ has more specific charge.

B. The proton has more specific charge.

C. The $\alpha-{particle}$ has more specific charge if its immersed in a medium with permittivity $\epsilon_0 = 81$ than in free space.

D. The proton has more specific charge if its immersed in a medium with permittivity $\epsilon_0 = 81$ than in free space.

Question 4

Chose the correct one

A. Kirchhoff’s loop rule is applied to a junction of incoming and outgoing current?

B. According to Kirchhoff’s loop rule a junction of incoming and outgoing current carries a potential proportional to the amount of current flowing through the junction.

C. Kirchhoff’s junction rule can be applied to a single current carrying path in any electric circuit.

D. The potential drop in a loop in any electric circuit is zero and its based on conservation of energy.

Question 5

Chose the correct one

A. Resultant of capacitance in series is more than individual resistances

B. Current division works on the basis of direct proportionality of resistances

C. Voltage division works on the basis of direct proportionality of resistances

D. Resistors in series will add up

Question 6

Ohms’ law corresponds to the following

A. Voltage and current are proportional even if resistance varies.

B. Conductivity is the ratio of current density and electric field.

C. Resistances must add up in parallel combination.

D. Linear relation between voltage and current can be accommodated to an arbitrary range of resistances.

Question 7

If we define a system-of-unit where permittivity of free space is 1 and electric field intensity E value is 1, which is the correct value for energy density?

A. $\frac{1}{2}$ B. $\frac{1}{3}$

C. 2 D. 3

Question 8

If we define a system-of-unit where capacitance of a configuration is 1 and potential difference of the same Is 1 what is the electrostatic energy of the capacitor?

A. $\frac{1}{2}$ B. $\frac{1}{3}$

C. 2 D. 3

Question 9

If $10$ electrons passing through an unit cross section area A constitute a current of $10 \times 1.6 \times 10^{-19}\,\frac{C}{s}$ flowing across it, whats the drift velocity of the electrons?

A. 1 unit B. 2 units C. 0.5 units D. 5 units

Question 10

A capacitor of $16 \,\mu F$ is filled with dielectric of dielectric strength $K = 5$ — or permittivity $\epsilon$ . Whats the new value of capacitance given a potential difference $V = 1000 \,volt$ is found on the capacitor.

A. $80 \,\mu F$ B. $\frac{16}{5} \,\mu F$

C. $\frac{5}{16} \,\mu F$ D. indeterminate