MCQ on Physics class 12 electric field and charges
- In the process of charging, the mass of the negatively charged body
- (a) Increases
- (b) Decreases
- (c) Remains constant
- (d) Is not related to the charging process
- A soap bubble is given a negative charge, its radius will
- (a) Increase
- (b) Decrease
- (c) Remain unchanged
- (d) Fluctuate
- For a uniformly charged ring of radius R, the electric field on its axis has the largest magnitude at a distance h from its center. Then the value of h is
- (a) R/√5
- (b) R
- (c) R/√2
- (d) R√2
- In a certain region of space with volume 0.2 m³, the electric potential is found to be 5V throughout. The magnitude of the electric field in this region is
- (a) 0.5 N/C
- (b) 1 N/C
- (c) 5 N/C
- (d) Zero
- A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of the resulting system
- (a) Increases by a factor of 4
- (b) Decreases by a factor of 2
- (c) Remains the same
- (d) Increases by a factor of 2
- The electric field required to keep a water drop of mass "m" just suspended when charged with one electron is
- (a) mg
- (b) mg/e
- (c) emg
- (d) em/g
- Example of a real-world Faraday cage is
- (a) Car
- (b) Plastic box
- (c) Lightning rod
- (d) Metal rod
- The potential on the hollow sphere of radius 1m is 1000V, then potential at 1/4m from the center of the sphere is
- (a) 1000V
- (b) 500V
- (c) 250V
- (d) Zero V
- If n capacitors, each of capacitance C, are connected in series, then the equivalent capacitance of the combination will be
- (a) nC
- (b) n²C
- (c) C/n
- (d) C/n²
- A metal foil of negligible thickness is introduced between two plates of a capacitor at the center. The capacitance of the capacitor will be
- (a) Same
- (b) Double
- (c) Half
- (d) K Times
- Identify the wrong statement in the following. Coulomb's law correctly describes the electric force that
- (a) Binds the electrons of an atom to its nucleus
- (b) Binds the protons and neutrons in the nucleus of an atom
- (c) Binds atoms together to form molecules
- (d) Binds atoms and molecules to form solids
- The dielectric constant of a metal is
- (a) 0
- (b) 1
- (c) Infinity
- (d) -1
- A parrot comes and sits on a bare high-power line. It will
- (a) Experience a mild shock
- (b) Experience a strong shock
- (c) Get killed instantaneously
- (d) Not be affected practically
- Which of the following is not based on the heating effect of current?
- (a) Electric heater
- (b) Electric bulb (with filament)
- (c) Electric iron
- (d) Microwave
- What gives the information on field strength, direction, and nature of the charge?
- (a) Electric current
- (b) Electric flux
- (c) Electric field
- (d) Electric potential
- In comparison with the electrostatic force between two electrons, the electrostatic force between two protons is
- (a) Greater
- (b) Smaller
- (c) Zero
- (d) Same
- A parallel plate capacitor is made by stacking n equally spaced plates connected alternatively. If the capacitance between any two adjacent plates is C, then resultant capacitance is
- (a) (n-1)C
- (b) (n+1)C
- (c) C
- (d) nC
- Each of two point charges is doubled and their distance is halved. The force of interaction becomes n times, where n is
- (a) 4
- (b) 1
- (c) 18
- (d) 16
- Charge on a conducting metal sphere is present
- (a) On the surface of the sphere
- (b) Inside the sphere
- (c) Outside the sphere
- (d) Both inside and outside of the sphere
PHYSICS MCQS UNIT 2
- SI unit of electric current is
- (a) coulomb
- (b) ampere
- (c) tesla
- (d) coulomb/ampere
- With the increase in area of cross section, the resistance of the conductor
- (a) increases
- (b) decreases
- (c) remains same
- (d) cannot say
- Which of the following has highest value of resistivity?
- (a) metals
- (b) non metals
- (c) alloys
- (d) none
- What is mobility?
- (a) Ratio of magnitude of drift velocity to electric field
- (b) Ratio of magnitude of electric field to magnitude of drift velocity
- (c) Dot Product of drift velocity and electric field
- (d) Cross product of drift velocity and electric field
- Which of the following has positive temperature coefficient of resistivity?
- (a) semiconductor
- (b) metals
- (c) insulators
- (d) All of these
- A wire is stretched to double of its original length, its new resistivity will
- (a) increase
- (b) decrease
- (c) may decrease or increase
- (d) remain same
- Current density is a
- (a) scalar
- (b) vector
- (c) Both a and b
- (d) none
- Kilowatt is a unit of
- (a) electric charge
- (b) electric energy
- (c) electric power
- (d) electric current
- Ohm's law is obeyed by
- (a) electrolytes
- (b) discharge tubes
- (c) vacuum tubes
- (d) None of these
- The relaxation time in conductors
- (a) increases with increase in temperature
- (b) decreases with increase in temperature
- (c) does not depend on temperature
- (d) first increases then decreases with rise in temperature
- The direction of flow of current through electric circuit is
- (a) from low to high potential
- (b) from high to low potential
- (c) does not depend on potential value
- (d) current cannot flow through circuit
- Resistivity of a wire depends on its
- (a) length
- (b) area of cross section
- (c) shape
- (d) material
- The drift velocity does not depend upon
- (a) cross section of the wire
- (b) length of the wire
- (c) number of free electrons
- (d) magnitude of the current
- Which of the following has negative temperature coefficient of resistance?
- (a) germanium
- (b) iron
- (c) aluminium
- (d) copper
- To draw maximum current from a combination of cells, how should the cells be grouped?
- (a) series
- (b) parallel
- (c) mixed
- (d) depends upon the relative values of external and internal resistance
Physics Multiple Choice Questions unit 3 MAGNETIC EFFECT OF CURRENT
- Tesla is a unit of:
- (a) Electric flux
- (b) Magnetic flux
- (c) Electric Field
- (d) Magnetic Field ✅
- Resistance of an ideal voltmeter is
- (a) Zero
- (b) Infinite ✅
- (c) High
- (d) Low
- When the charged particles move in a combined magnetic and electric field, then the force acting is known as
- (a) Centripetal force
- (b) Centrifugal force
- (c) Lorentz force ✅
- (d) Orbital force
- Magnetic field at any point inside the straight solenoid is given as
- (a) B = μ₀ + nl
- (b) B = μ₀ + n
- (c) B = μ₀/nl
- (d) B = μ₀nl ✅
- The force on a current-carrying conductor when placed perpendicular in a uniform magnetic field.
- (a) F=BIL ✅
- (b) F=B/IL
- (c) F=L/BI
- (d) F=I/BL
- A soft iron bar is introduced inside a current-carrying solenoid. The magnetic field inside a solenoid:
- (a) Decrease
- (b) Will increase ✅
- (c) Will become zero
- (d) Will remain unaffected
- A positive charge is moving upward in a magnetic field directed towards North. The particle will be deflected towards:
- (a) East
- (b) North
- (c) South
- (d) West ✅
- Write the dimensional formula of magnetic flux
- (a) M⁰L⁻¹T⁰A⁻¹
- (b) M¹L⁰T⁻²A⁻¹
- (c) ML²T⁻²A⁻¹ ✅
- (d) M⁰L¹T⁰A¹
- What is the resistance of an ideal voltmeter and an ideal ammeter?
- (a) Infinity, Zero ✅
- (b) Zero, Infinity
- (c) Zero, Zero
- (d) Infinity, Infinity
- Weber ampere per meter is equal to
- (a) Joule
- (b) Newton ✅
- (c) Henry
- (d) Watt
- A frog can jump higher than normal in a magnetic field because the tissue of a frog is:
- (a) Paramagnetic
- (b) Diamagnetic ✅
- (c) Ferromagnetic
- (d) Anti-Ferromagnetic
- The path executed by charged particle whose motion is perpendicular to a uniform magnetic field is:
- (a) A straight path
- (b) An ellipse
- (c) A circle ✅
- (d) A helix
- In a moving coil galvanometer, we use radial magnetic field so that the scale is:
- (a) Logarithmic
- (b) Exponential
- (c) Linear ✅
- (d) None of these
- Magnetic susceptibility for diamagnetic material is
- (a) Small and negative ✅
- (b) Small and positive
- (c) Large and positive
- (d) Large and negative
- The field due to a long straight wire carrying a current I is proportional to:
- (a) r
- (b) r²
- (c) 1/r²
- (d) 1/r ✅
- Magnetic effect of current was discovered by:
- (a) Faraday
- (b) Oersted ✅
- (c) Ampere
- (d) Bohr
- A charged particle enters a magnetic field at an angle of 60° with the magnetic field. The path of the particle will be:
- (a) A helix ✅
- (b) An ellipse
- (c) A circle
- (d) A straight line
- To convert a galvanometer into an ammeter, we connect
- (a) Low resistance in parallel ✅
- (b) High resistance in series
- (c) High resistance in parallel
- (d) Low resistance in series
Multiple Choice Questions Unit 4 Electromagnetic Induction and Alternating Current
- Which of the following laws give the polarity of induced emf?
- (a) Biot–Savart’s law
- (b) Lenz’ law (✔)
- (c) Faraday’s law
- (d) Coulomb’s law
- Electrical inertia is the measure of:
- (a) Self inductance (✔)
- (b) Mutual inductance
- (c) Impedance
- (d) Reactance
- Dimensional formula of inductance is:
- (a) [M L³ T⁻² A²]
- (b) [M L² T⁻² A]
- (c) [M L² T⁻² A²]
- (d) [M L² T⁻² A⁻²] (✔)
- Direction of current induced in a wire moving in magnetic field is given by:
- (a) Fleming’s left hand rule (✔)
- (b) Fleming’s right hand rule
- (c) Right hand thumb rule
- (d) SNOW rule
- If N-pole of a bar magnet goes away from the coil, direction of current induced in it will be:
- (a) Anti-clockwise (✔)
- (b) Clockwise
- (c) Either ‘a’ or ‘b’
- (d) Can’t say
- Coils in a resistance box are doubly wound to:
- (a) Increase self-induction
- (b) Decrease self-induction (✔)
- (c) Increase resistance
- (d) Decrease resistance
- At resonant frequency, the impedance of LCR circuit is:
- (a) Zero
- (b) Maximum
- (c) Minimum (✔)
- (d) Infinite
- Power dissipation is maximum for:
- (a) Pure capacitive circuit
- (b) Pure inductive circuit
- (c) Pure resistive circuit (✔)
- (d) All of these
- If frequency of AC increases, then inductive reactance:
- (a) Increases (✔)
- (b) Decreases
- (c) Remains same
- (d) Becomes zero
- Power factor is unity for:
- (a) Pure capacitive circuit
- (b) Pure resistive circuit (✔)
- (c) Pure inductive circuit
- (d) All of these
- If frequency of AC is doubled, then capacitive reactance will be:
- (a) Same
- (b) Doubled
- (c) Halved (✔)
- (d) Zero
- Transformation ratio in a step up transformer is:
- (a) 1
- (b) Less than 1
- (c) Greater than 1 (✔)
- (d) Zero
- Energy loss due to eddy currents in a transformer can be minimised using:
- (a) Copper coils
- (b) Thick coils
- (c) Solid core
- (d) Laminated core (✔)
- If current lags behind voltage by a phase difference of π/2, then the AC circuit contains:
- (a) Only ‘R’
- (b) Only ‘C’
- (c) Only ‘L’ (✔)
- (d) Both ‘L’ and ‘R’
- A transformer steps up or down:
- (a) Voltage (✔)
- (b) Current
- (c) Power
- (d) Frequency
Multiple Choice Questions
-
In electromagnetic waves, the phase difference between electric and magnetic field vectors is:
- (a) zero
- (b) π/4
- (c) π/2
- (d) π
Answer: (a)
-
Which of the following has the minimum wavelength?
- (a) Blue light
- (b) γ-rays
- (c) Infrared rays
- (d) Microwave
Answer: (b)
-
The correct option for the speeds of gamma rays, X-rays, and microwaves (Vg, Vx, Vm) is:
- (a) Vg > Vx > Vm
- (b) Vg < Vx < Vm
- (c) Vg > Vx > Vm
- (d) Vg = Vx = Vm
Answer: (d)
-
Which of the following has maximum penetrating power?
- (a) Ultraviolet radiation
- (b) Microwaves
- (c) γ-rays
- (d) Radio waves
Answer: (c)
-
The quantity √𝜇o𝜀o represents:
- (a) Speed of sound
- (b) Speed of light in vacuum
- (c) Speed of e.m. waves
- (d) Inverse of speed of light in vacuum
Answer: (d)
-
Which of the following is called heat radiation?
- (a) X-rays
- (b) γ-rays
- (c) Infrared radiation
- (d) Microwave
Answer: (c)
-
From Maxwell’s hypothesis, a changing electric field gives rise to:
- (a) An electric field
- (b) An induced e.m.f
- (c) A magnetic field
- (d) A magnetic dipole
Answer: (c)
-
The ultra-high frequency band of radio waves in electromagnetic waves is used as in:
- (a) Television waves
- (b) Cellular phone communication
- (c) Commercial FM radio
- (d) Both (a) and (c)
Answer: (b)
-
Electromagnetic waves are transverse in nature as evident by:
- (a) Polarisation
- (b) Interference
- (c) Reflection
- (d) Diffraction
Answer: (a)
-
Which of the following are not electromagnetic waves?
- (a) Cosmic rays
- (b) γ-rays
- (c) β-rays
- (d) X-rays
Answer: (c)
-
In electromagnetic waves, the phase difference between electric and magnetic field vectors is:
- (a) zero
- (b) π/4
- (c) π/2
- (d) π
Answer: (a)
-
Which of the following has the minimum wavelength?
- (a) Blue light
- (b) γ-rays
- (c) Infrared rays
- (d) Microwave
Answer: (b)
-
The correct option for the speeds of gamma rays, X-rays, and microwaves (Vg, Vx, Vm) is:
- (a) Vg > Vx > Vm
- (b) Vg < Vx < Vm
- (c) Vg > Vx > Vm
- (d) Vg = Vx = Vm
Answer: (d)
-
Which of the following has maximum penetrating power?
- (a) Ultraviolet radiation
- (b) Microwaves
- (c) γ-rays
- (d) Radio waves
Answer: (c)
-
The quantity √𝜇o𝜀o represents:
- (a) Speed of sound
- (b) Speed of light in vacuum
- (c) Speed of e.m. waves
- (d) Inverse of speed of light in vacuum
Answer: (d)
-
Which of the following is called heat radiation?
- (a) X-rays
- (b) γ-rays
- (c) Infrared radiation
- (d) Microwave
Answer: (c)
-
From Maxwell’s hypothesis, a changing electric field gives rise to:
- (a) An electric field
- (b) An induced e.m.f
- (c) A magnetic field
- (d) A magnetic dipole
Answer: (c)
-
The ultra-high frequency band of radio waves in electromagnetic waves is used as in:
- (a) Television waves
- (b) Cellular phone communication
- (c) Commercial FM radio
- (d) Both (a) and (c)
Answer: (b)
-
Electromagnetic waves are transverse in nature as evident by:
- (a) Polarisation
- (b) Interference
- (c) Reflection
- (d) Diffraction
Answer: (a)
-
Which of the following are not electromagnetic waves?
- (a) Cosmic rays
- (b) γ-rays
- (c) β-rays
- (d) X-rays
Answer: (c)
-
The structure of solids is investigated by using:
- (a) Cosmic rays
- (b) X-rays
- (c) γ-rays
- (d) Infrared rays
Answer: (b)
-
Maxwell introduced the concept of:
- (a) AC current
- (b) Displacement current
- (c) Impedance
- (d) Reactance
Answer: (b)
-
Electromagnetic waves with wavelength λ are used by an FM radio station for broadcasting. Here, λ belongs to:
- (a) Radio waves
- (b) VHF radio waves
- (c) UHF radio waves
- (d) Microwaves
Answer: (b)
-
The conduction current is the same as the displacement current when the source is:
- (a) AC only
- (b) DC only
- (c) Either AC or DC
- (d) Neither AC nor DC
Answer: (c)
-
If a variable frequency AC source is connected to a capacitor, then with a decrease in frequency, the displacement current will:
- (a) Increase
- (b) Decrease
- (c) Remain constant
- (d) First decrease, then increase
Answer: (b)
-
Which of the following electromagnetic waves is used in medicine to destroy cancer cells?
- (a) IR-rays
- (b) Visible rays
- (c) Gamma rays
- (d) Ultraviolet rays
Answer: (c)
