Q1
mcq
1 mark
According to Coulomb's law, electrostatic force F between two point charges separated by the distance r varies as
- A. $F \propto \frac{1}{r}$
- B. $F \propto r$
- C. $F \propto \frac{1}{r^2}$
- D. $F \propto r^2$
Correct Answer: C —
Solution
Coulomb's law states that the electrostatic force between two point charges is inversely proportional to the square of the distance between them, mathematically expressed as $F \propto \frac{1}{r^2}$.
Q2
mcq
1 mark
The maximum electric field that a dielectric medium can withstand without breakdown of dielectric property is
- A. dielectric constant
- B. dielectric strength
- C. dielectric polarization
- D. electrical susceptibility
Correct Answer: B —
Solution
Dielectric strength is defined as the maximum electric field that a dielectric material can withstand without undergoing electrical breakdown (i.e., becoming conductive).
Q3
mcq
1 mark
The electric current per unit area of cross-section of a conductor is called
- A. Conductivity
- B. Resistivity
- C. Current density
- D. Mobility
Correct Answer: C —
Solution
Current density is defined as the electric current $I$ passing per unit area $A$ of cross-section of a conductor, denoted as $J = \frac{I}{A}$.
Q4
mcq
1 mark
A Galvanometer which is converted to ammeter has
- A. low resistance in series
- B. low resistance in parallel
- C. high resistance in series
- D. high resistance in parallel
Correct Answer: B —
Solution
To convert a galvanometer into an ammeter, a very low resistance called a shunt must be connected in parallel with the galvanometer to allow most of the current to bypass the meter.
Q5
mcq
1 mark
The substances which have the tendency to move from stronger to weaker part of external magnetic field are
- A. Diamagnetic
- B. Ferromagnetic
- C. Paramagnetic
- D. Ferro and Paramagnetic
Correct Answer: A —
Solution
Diamagnetic substances are characterized by their tendency to move from a region of stronger magnetic field to a region of weaker magnetic field when placed in a non-uniform external magnetic field.
Q6
mcq
1 mark
A long straight wire having increasing current at steady rate is placed along the axis of a circular metal ring as shown in the figure. When viewed from above towards the ring, the wire
- A. induces clockwise current in the ring
- B. induces anti-clockwise current in the ring
- C. does not induce current in the ring
- D. induces current in the ring which changes its direction with respect to time
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Q6
mcq
A long straight wire having increasing current at steady rate is placed along the axis of a circular conducting ring with plane of the ring perpendicular to the plane of paper. When viewed from above towards the ring, the wire
- A. induces clockwise current in the ring
- B. induces anti-clockwise current in the ring
- C. does not induce current in the ring
- D. induces current in the ring, which changes its direction with respect to time.
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Q7
mcq
1 mark
A transformer works on the principle of
- A. Mutual induction
- B. Self induction
- C. Force on coil in magnetic field
- D. Torque on coil in magnetic field
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Q8
mcq
1 mark
The existence of electromagnetic waves by a set of equations was given by
- A. Michel Faraday
- B. Andre Ampere
- C. Albert Einstein
- D. JC Maxwell
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Q9
mcq
1 mark
The relation between focal length f and radius of curvature R of a spherical mirror is
- A. R = f
- B. R = f/2
- C. f = R/2
- D. f = 1/R
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Q10
mcq
1 mark
Statement I : Wave fronts obtained from a point source of light in an isotropic medium are always spherical at finite distance.
Statement II : Speed of light in an isotropic medium is constant.
- A. Only Statement I is correct
- B. Only Statement II is correct
- C. Both Statement I and Statement II are wrong
- D. Both Statement I and Statement II are correct
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Q11
mcq
1 mark
Which of the following phenomenon confirms the transverse nature of light waves?
- A. Diffraction
- B. Polarization
- C. Interference
- D. Reflection
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Q12
mcq
1 mark
Emission of electrons from a metal surface by heating is called as
- A. Photo-electric emission
- B. Field emission
- C. Secondary emission
- D. Thermionic emission
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Q13
mcq
1 mark
Bohr's atom model is applicable to only
- A. Hydrogen atom
- B. Gold atom
- C. Silver atom
- D. Oxygen atom
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Q14
mcq
1 mark
Match the following columns:
Column - I Column - II
a) Isotopes i) Nucleii having same number of neutrons
b) Isobars ii) Nucleii having same number of protons
c) Isotones iii) Nucleii having same number of nucleons
- A. a – ii, b – iii, c – i
- B. a – iii, b – ii, c – i
- C. a – ii, b – i, c – iii
- D. a – iii, b – i, c – ii
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Q14
mcq
Match the following columns:
Column - I
a) Isotopes
b) Isobars
c) Isotones
Column - II
i) Nucleii having same number of neutrons
ii) Nucleii having same number of protons
iii) Nucleii having same number of nucleons
- A. a – ii, b – iii, c – i
- B. a – iii, b – ii, c – i
- C. a – ii, b – i, c – iii
- D. a – iii, b – i, c – ii
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Q15
mcq
1 mark
The impurity atoms added to a pure semiconductor crystal to convert it into p-type semiconductor are
- A. tetravalent
- B. trivalent
- C. pentavalent
- D. hexavalent
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Q16
short answer
1 mark
In a charge distribution, the ratio of electric charge to the length is _______ charge density.
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Q17
short answer
1 mark
_______ is equal to work done to transfer unit positive test charge from infinity to a point in electric field opposite to field.
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Q18
short answer
1 mark
An example for ferromagnetic substance is ________.
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Q19
short answer
1 mark
The phase difference between peak value of voltage and current in a pure resistive circuit is ________.
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Q20
short answer
1 mark
The bottom of a tank filled with water appears to be raised, it is due to ________ of light.
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Q21
short answer
2 marks
Give any two properties of electric field lines.
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Q22
short answer
2 marks
Calculate the force on a point charge of $2.0 \times 10^{-6} \text{ C}$ placed in a uniform electric field of $0.8 \text{ NC}^{-1}$.
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Q23
short answer
2 marks
State Kirchhoff's rules of electrical networks.
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Q24
short answer
2 marks
Mention any two factors on which current sensitivity of a galvanometer depends.
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Q25
short answer
2 marks
Draw a neat diagram of a simple a.c. generator and label the parts.
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Q26
short answer
2 marks
Write the expression for average power in an a.c LCR circuit and explain the terms.
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Q27
short answer
2 marks
Mention any two uses of infrared radiations.
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Q28
short answer
2 marks
a) Draw a diagram of unbiased depletion region of p-n junction showing immobile charges.
b) What is meant by rectification?
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Q29
short answer
3 marks
a) What is meant by an equipotential surface?
b) Draw equipotential surfaces for uniform electric field and a point charge.
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Q30
long answer
3 marks
Derive an expression for magnetic field due to a straight infinite conductor carrying current using Ampere's circuital law.
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Q31
short answer
3 marks
Define a) magnetic susceptibility and b) magnetic relative permeability and write an expression relating them.
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Q32
short answer
3 marks
a) What is meant by electromagnetic induction?
b) State and explain Faraday's law of electromagnetic induction.
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Q33
short answer
3 marks
Calculate resonant angular frequency of a series LCR a.c. circuit.
Given $R = 100\Omega$, $L = 1.0\text{ mH}$ and $C = 1.0\text{ nF}$
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Q34
short answer
3 marks
Write the two conditions for total internal reflection of light and mention its one technological application.
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Q35
long answer
3 marks
Deduce an expression for total energy of electron in an orbit of hydrogen atom in terms of radius of orbit.
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Q36
short answer
3 marks
a) What is meant by Nuclear fusion? Explain.
b) Why it is called thermonuclear reaction?
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Q37
long answer
5 marks
Deduce an expression for electric field at a point outside a thin uniformly-charged spherical shell using Gauss's law.
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Q38
long answer
5 marks
Obtain an expression for electrical conductivity of conducting electrons in a metallic conductor in terms of charge (e) and mass (m) of the electrons.
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Q39
long answer
5 marks
Derive an expression for magnetic field at a point on the axis of a circular current loop.
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Q40
long answer
5 marks
a) Prove Snell's law of refraction of light, when a plane wavefront passes from rarer to denser medium.
b) Mention any two uses of polaroids.
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Q41
long answer
5 marks
a) Explain the classification of solids using band theory.
b) Give any two differences between intrinsic and extrinsic semiconductors.
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Q42
long answer
5 marks
A network of four $9\mu\text{F}$ capacitors is connected to a 300V supply as shown in figure. Determine a) Equivalent capacitance of the network and b) The charge on each capacitor.
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Q42
long answer
Four $9\mu\text{F}$ capacitors are connected at each side of a square. A 300V supply is connected across adjacent corners of the square. Determine a) Equivalent capacitance across adjacent corners of square and b) the charge on each capacitor.
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Q43
long answer
5 marks
Two cells $8\text{V}, 1\Omega$ and $10\text{V}, 2\Omega$ are connected in parallel such that they send currents in the same direction through an external resistance $20\Omega$. Find the current and potential difference across $20\Omega$.
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Q44
long answer
5 marks
A sharp object of height $3.0\text{ cm}$ is placed at $21\text{ cm}$ in front of a convex lens of focal length $14\text{ cm}$. Find the position and magnification of the image. What happens to the height of the image if the object is moved further away from the lens?
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Q45
long answer
5 marks
The work function of a metal is $2.20\text{ eV}$ when radiation of frequency $6.50 \times 10^{14}\text{ Hz}$ incident on the metal surface photo emission of electrons occurs. Calculate a) energy of incident photon and b) stopping potential of photoelectrons. (Given $h = 6.63 \times 10^{-34}\text{ Js}$ and $e = 1.6 \times 10^{-19}\text{C}$)
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