KCET Sample Paper Physics

Sample Paper

Physics

Q.No. 1 A piece of copper is to be shaped into a conducting wire of maximum resistance. The suitable length
and diameter are _______ and _______ respectively.

(A) L and d

(B) 2 L and d

(C) L/2 and 2 d

(D) 2 L and d/2

Q.No. 2 Coercivity of a magnet where the ferromagnet gets completely demagnetized is 3 x 103 Am-1. The
minimum current required to be passes in a solenoid having 1000 turns per metre, so that the magnet gets
completely demagnetized when placed inside the solenoid is

(A) 30mA

(B) 60 mA

(C) 3A

(D) 10 A

Q.No. 3 According to Cartesian sign convention, in ray optics

(A) all distances are taken positive

(B) all distances are taken negative

(C) all distances in the direction of incident ray are taken positive

(D) all distances in the direction of incident ray are taken negative

Q.No. 4 One mole of O2 gas is heated at constant pressure starting at 27 °C. How much energy must be
added to the gas as heat to double its volume?

(A) Zero

(B) 450R

(C) 750R

(D) 1050R

Q.No. 5 A mass of 1 kg carrying a charge of 2 C is accelerated through a potential of 1 V. The velocity
acquired by it is

(A) √2 ms-1

(B) 2ms-1

(C) 1/√2 ms-1

(D) 1/2 ms-1

Q.No. 6 An electric dipole is kept in non-uniform electric field. It generally experiences

(A) A force and torque

(B) A force but not a torque

(C) A torque but not a force

(D) Neither a force nor a torque

Q.No. 7 Two spheres of electric charges +2 nC and −8 nC are placed at a distance ‘d’ apart. If they are
allowed to touch each other, what is the new distance between them to get a repulsive force of same
magnitude as before?

(A) 4d

3

(B) 3d

4

(C) d

(D) d

2

Q.No. 8 The number of turns in a coil of Galvanometer is tripled, then

(A) Voltage sensitivity increases 3 times and current sensitivity remains constant

(B) Voltage sensitivity remains constant and current sensitivity increases 3 times

(C) Both voltage and current sensitivity remains constant

(D) Both voltage and current sensitivity decreases by 33%

Q.No. 9 The dimensions of the ratio of magnetic flux (ϕ) and permeability (μ) are

(A) [M0 L1 T0 A1 ]

(B) [M0 L-3 T0 A1 ]

(C) [M0 L1 T1 A-1 ]

(D) [M0 L2 T0 A1 ]

Q.No. 10 The period of revolution of an electron in the ground state of a hydrogen atom is T. The period of
revolution of the electron in the first excited state is

(A) 2T

(B) 4T

(C) 6T

(D) 8T

Q.No. 11 The total energy of an electron revolving in the second orbit of hydrogen atom is

(A) -13.6eV

(B) -1:51eV

(C) -3.4eV

(D) Zero

Q.No. 12 A 100 W bulb is connected to an AC ’ source of 220 V, 50 Hz. Then the current flowing through the
bulb is

(A) 5/11 A

(B) ½ A

(C) 2 A

(D) ¾ A

Q.No. 13 Due to Doppler’s effect the shift in wavelength observed is 0.1Å for a star producing wavelength
6000 Å. Velocity of recession of the star will be

(A) 25 km/s

(B) 10 km/s

(C) 5 km/s

(D) 20 km/s

Q.No. 14 The correct Biot-Savart law in vector form is
→ →
→
(A) dB = μ0 I(dl×r)
2
4π r

→ →
→
(B) dB =
μ0 I(dl×r)
3
4π r

→ →
(C) dB = μ0

4π
Idl

r
2

→ →
(D) dB = μ0

4π
Idl

r
3

Q.No. 15 A cylindrical container containing water has a small hole at height of H = 8 cm from the bottom
and at a depth of 2cm from the top surface of the liquid. The maximum horizontal distance travelled by the

water before it hits the ground (x) is

(A) 8 cm

(B) 4√2 cm

(C) 4cm

(D) 6 cm

Q.No. 16 The conductivity of semiconductor increases with increase in temperature because

(A) number density of charge carriers increases

(B) relaxation time increases

(C) both number density of charge carriers and relaxation time increase

(D) number density of current carriers increases, relaxation time decreases but effect of decrease in
relaxation time is much less than increase in number density

Q.No. 17 The energy equivalent to a substance of mass 1 gis

(A) 18x1013 J

(B) 9x1013 J

(C) 18x106 J

(D) 9x106J

Q.No. 18 In the series LCR circuit, the power dissipation is through

(A) R

(B) L

(C) C

(D) Both Land C

Q.No. 19

The magnetic fields at the centre ‘O’ in the given figure is

(A) 7

14
μ0I

R

(B) 5

12
μ0I

R

μ0I
(C) 3

10 R

(D) μ0I

R

Q.No. 20 Two balls are thrown simultaneously in air. The acceleration of the centre of mass of the two balls
when in air,

(A) depends on the masses of the two balls

(B) depends on the speeds of the two balls

(C) isequal to g (Acceleration due to gravity)

(D) depends on the direction of motion of the two balls.

Q.No. 21 The pressure at the bottom of a liquid tank is not proportional to the

(A) Acceleration due to gravity

(B) Density of the liquid

(C) Height of the liquid

(D) Area of the liquid surface

Q.No. 22 The radius of the Earth is 6400 km. If the height of an antenna is 500 m, then its range is

(A) 800 km

(B) 100 km

(C) 80 km

(D) 10 km

Q.No. 23 First overtone frequency of a closed pipe of length ‘l1,’ is equal to the 2nd harmonic frequency of
an open pipe of length ‘l2’ The ratio l1/l2

(A) 3/4

(B) 4/3

(C) 3/2

(D) 2/3

Q.No. 24 In metre bridge experiment, with a standard resistance in the right gap and a resistance coil dipped
in water (in a beaker) in the left gap, the balancing length obtained is ‘l’. If the temperature of water is
increased, the new balancing length is

(A) > I

(B) < I

(C) = I

(D) = 0

Q.No. 25 The dc common emitter current gain of a n-p-n transistor is 50 . The potential difference is 50 . The
potential difference applied across the collector and emitter of a transistor used in CE configuration is, VCE =
2 V. If the collector resistance, Rc = 4 kΩ, the base current (IB) and the collector current (Ic) are

(A) IB = 10μA, IC = 0.5 mA

(B) IB = 0.5pA, IC = 10 mA

(C) IB = 5μA, IC = 1mA

(D) IB 1μA, IC 0.5 mA

Q.No. 26 The output of a step down transformer is measured to be 48 V when connected to a 12 W bulb. The
value of peak current is

(A) 1

√2
A

(B) √2A

(C) 2√ 2
1
A

(D) 1

4
A

Q.No. 27 If P, Q and R are physical quantities having different dimensions, which of the following
combinations can never be a meaningful quantity?

(A) P −Q

R

(B) PQ - R

(C) PQ/R
2

(D) PR−Q

R

Q.No. 28 A satellite is orbiting close to the earth and has a kinetic energy K. The minimum extra kinetic
energy required by it just overcome the gravitational pull of the earth is

(A) K

(B) 2k

(C) √3K

(D) 2√2 K

Q.No. 29 Two wires A and B are stretched by the same load. If the area of cross-section of wire ‘A’ is double
that of ‘B’, then the stress on ‘B’ is

(A) Equal to that on A

(B) Twice that on A

(C) Halfthat on A

(D) Four times that on A

Q.No. 30 An electromagnetic wave is travelling in x-direction with electric field vector given by,
→
Ey = E0 sin(kx − ωt)^
j . The correct expression for magnetic field vector is

→
(A) B = E C sin(kx − ωt)^j
y 0

→
(B) B = E C sin(kx − ωt)^j
z 0

→
(C) B = y
E0

C
sin(kx − ωt)^
j

→
(D) B = z
E0

C
sin(kx − ωt)^
j

Q.No. 31 A circular current loop of magnetic moment M is in a arbitrary orientation in an external uniform
→
magnetic field B. The work done to rotate the loop by 30° about an axis perpendicular to its plane is

(A) MB

(B) √3 MB

2

(C) MB/2

(D) Zero

Q.No. 32 The S.I. unit of specific heat capacity is

(A) Jmol −1
K
−1

(B) Jkg −1
K
−1

(C) JK −1

(D) Jkg −1

Q.No. 33 In Young’s double slit experiment, two wavelengths λ1 = 780 nm used to wavelengths and λ2 = 520
nm interference fringes. If the nth bright are obtain band due to A, coincides with (n + 1)th bright band due to
λ2, then the value of n is

(A) 4

(B) 3

(C) 2

(D) 6

Q.No. 34 An electron is moving in a circle of radius r in a uniform magnetic field B. Suddenly the field is
reduced to B/2: The radius of the circular path now becomes

(A) r/2

(B) 2r

(C) r/4

(D) 4r

Q.No. 35 Light of certain frequency and intensity incident on a photosensitive material causes photoelectric
effect. If both the frequency and intensity are doubled, the photoelectric saturation current becomes.

(A) quadruple

(B) doubled

(C) halved

(D) unchanged

→
Q.No. 36 An object with mass 5 kg is acted upon by a force, F = (−3^i + 4^j)N If its initial velocity at
→ = (3^i + 12^j) , the time at which it will just have a velocity along y-axis is
t = 0 is v

(A) 5 s

(B) 10 s

(C) 2 s

(D) 15 s

Q.No. 37 An inductor of inductance L and resistor R are joined together in series and connected by a source
of frequency . The power dissipated in the circuit is

(A)
2 2 2
R +ω L

V

(B)
2
v R
2 2 2
R +ω L

(C) 2
R +ω L
v
2 2

2

(D) v R

√ R2+ω2L2

Q.No. 38 A certain charge 2Q is divided at first into two parts q1 and q2. Later the charges are placed at a
certain distance. If the force of interaction between two charges is maximum then Q/q =

(A) 4

(B) 2

(C) 1

(D) 0.5

Q.No. 39 A space station is at a height equal to the radius of the Earth. If ‘vE is the escape velocity on the
surface of the Earth, the same on the space station is __________times ‘vE:

(A) 1/2

(B) 1/4

(C) 1/√2

(D) 1/√3

Q.No. 40 The phenomenon involved in the reflection of radio-waves by ionosphere is similar to

(A) reflection of light by plane mirror

(B) total internal reflection of light in air during a mirage

(C) dispersion of light by water molecules during the formation

(D) scattering of light by air particles

Q.No. 41 A system of 2 capacitors of capacitance 2 μ F and 4 μ F is connected in series across a potential
difference of 6V. The electric charge and energy stored in the system are

(A) 10 μ C and 30 μ J

(B) 36 μ C and 108 μ J

(C) 8 μ C and 24 μ J

(D) 1 μ C and 3 μ J

Q.No. 42 A magnetic needle has a magnetic moment of 5 x 10-2 Am2 and moment of inertia 7.8 x 10-6
→ . The magnitude of magnetic field is
kgm2. It has a period of oscillation of 2s in a magnetic field B
approximately?

(A) 1.6 x 10-4 T

(B) 0.4 x 10-4 T

(C) 3.2 x 10-4 T

(D) 0.0016 T

Q.No. 43 A particle is dropped from a height ‘H’. The de’Broglie wavelength of the particle depends on
height as

(A) H

(B) H0

(C) H1/2

(D) H −1/2

Q.No. 44 A cup of tea cools from 65°5°C to 62:5°C in 1 minute in a room at 22:5°C. How long will it take to
cool from 46°5°C to. 40-5°C in the same room ?

(A) 4 minutes

(B) 2 minutes

(C) 1minute

(D) 3 minutes

Q.No. 45 The magnetic field at the center of a current carrying loop of radius 0.1 m is 5√5 times that at a
point along its axis. The distance of this point from the centre of the loop is

(A) 0.2 m

(B) 0.1 m

(C) 0.05 m

(D) 0.25 m

→ →
Q.No. 46 An electron is moving with an initial velocity v = v ^i and is in a uniform magnetic field B = b ^j.
0 0

Then its de Broglie wavelength

(A) remains constant

(B) increases with time

(C) decrease with time

(D) increase and decrease periodically

Q.No. 47 A hydrogen atom in ground state absorbs 10.2 eV of energy. The orbital angular momentum of the
electron is increased by

(A) 1.05 x 10-34 Js

(B) 2.11 x 10-34Js

(C) 3.16 x 10-34Js

(D) 4.22 x 10-34Js

Q.No. 48 A magnetic dipole of magnetic moment 6 × 10 Am and moment of inertia 12 × 10 kgm
−2 2 −6 2

performs oscillations in a magnetic field of 2 × 10 T. The time taken by the dipole to complete 20
−2

oscillations is (π ≃ 3)

(A) 36 s

(B) 6 s

(C) 12 s

(D) 18 s

Q.No. 49 The force of repulsion between two identical positive charges when kept with a separation ‘r’ in air
is ‘F’. Half the gap between the two charges is filled by a dielectric slab of dielectric constant = 4. Then the
new force of repulsion between those two charges becomes

(A) F/3

(B) F/2

(C) F/4

(D) 4F/9

Q.No. 50 The strength of the Earth’s magnetic field

(A) Constant everywhere

(B) Zero everywhere

(C) Having very high value

(D) Varying from place to place on the Earth’s surface

Q.No. 51 For which combination of working temperatures, the efficiency of ‘Carnot’s engine’ is the least ?

(A) 60 K, 40 K

(B) 40 K, 20 K

(C) 80 K, 60 K

(D) 100 K, 80 K

Q.No. 52 Frequency of revolution of an electron revolving in nth orbit of H-atom is proportional to

(A) 1

n
2

(B) n

(C) n independent of n

(D) 1

n
3

Q.No. 53 In the three parts of a transistor, ‘Emitter’ is of

(A) moderate size and heavily doped

(B) large size and lightly doped

(C) thin size and heavily doped

(D) large size and moderately doped

Q.No. 54 A motor pump lifts 6 tonnes of water from a well of depth 2 m to the first floor of height 35 m from
the ground floor in 20 minutes. The power of the pump (in kW) is [g = 10 ms ]. −2

(A) 1.85

(B) 6

(C) 3

(D) 12

Q.No. 55 A block rests on a rough inclined plane making an angle of 30° with the horizontal. The coefficient
of static friction between the block and the plane is 0.8. If the frictional force on the block is 10 N, the mass
of the block is (g = 10 ms-2)

(A) 2.0

(B) 4.0

(C) 1.6

(D) 2.5

Q.No. 56 Kirchhoff’s junction rule is a reflection of

(A) Conservation of current density vector

(B) Conservation of energy

(C) Conservation of momentum

(D) Conservation of charges

Q.No. 57 A basic communication system consists of (a) Transmitter (b) Information source (c) User of

information (d) Channel (e) Receiver The correct sequence of the arrangement is

(A) a, b, c, d and e

(B) b, a, d, e and c

(C) b, d, a, c and e

(D) b, e, a, d and c

Q.No. 58 The resistance R= V/I where V = (100 ± 5) V and I = (10 ± 0.2) A. The percentage error in R is

(A) 5.2%

(B) 4.8%

(C) 7%

(D) 3%

Q.No. 59 An aluminium sphere is dipped into water. Which of the following is true?

(A) Buoyancy will be less in water at 0°C than that in water at 4°C

(B) Buoyancy will be more in water at 0°C than that in water at 4°C

(C) Buoyancy in water at 0°C will be same as that in water at 4°C

(D) Buoyancy may be more or less in water at 4°C depending on the radius of the sphere

Q.No. 60 Three point charges of + 2q, + 2q and − 4q are placed at the corners A, B and C of an equilateral
triangle ABC of side ‘x’. The magnitude of the electric dipole moment of this system is

(A) 2 qx

(B) 2√3qx

(C) 3√2qx

(D) 3 qx

Answer Sheet
Q.No Answer
Q.No. 1 (D)
Q.No. 2 (C)
Q.No. 3 (C)
Q.No. 4 (D)
Q.No. 5 (B)
Q.No. 6 (A)
Q.No. 7 (B)
Q.No. 8 (B)
Q.No. 9 (A)

Q.No. 10 (D)
Q.No. 11 (C)
Q.No. 12 (A)

Q.No. 13 (C)
Q.No. 14 (B)
Q.No. 15 (A)
Q.No. 16 (D)
Q.No. 17 (B)
Q.No. 18 (B)
Q.No. 19 (B)
Q.No. 20 (C)
Q.No. 21 (D)
Q.No. 22 (C)
Q.No. 23 (A)
Q.No. 24 (A)
Q.No. 25 (A)
Q.No. 26 (C)
Q.No. 27 (A)
Q.No. 28 (A)
Q.No. 29 (B)
Q.No. 30 (D)
Q.No. 31 (D)
Q.No. 32 (B)
Q.No. 33 (C)
Q.No. 34 (B)
Q.No. 35 (B)
Q.No. 36 (B)
Q.No. 37 (B)
Q.No. 38 (C)
Q.No. 39 (C)
Q.No. 40 (B)
Q.No. 41 (C)
Q.No. 42 (D)
Q.No. 43 (D)
Q.No. 44 (A)
Q.No. 45 (A)
Q.No. 46 (A)
(A)

Q.No. 47
Q.No. 48 (C)
Q.No. 49 (D)
Q.No. 50 (D)

Q.No. 51 (D)
Q.No. 52 (D)
Q.No. 53 (A)
Q.No. 54 (C)
Q.No. 55 (A)
Q.No. 56 (D)
Q.No. 57 (B)
Q.No. 58 (C)
Q.No. 59 (A)
Q.No. 60 (B)