class 11 physics model question solution
The Solution pdf contains the solution of following questions :-
1.
A metre rule is used to measure the length of a piece of string in a
certain
experiment. It is found to be 20 cm long to the nearest millimeter. How
should this
result be recorded in a table of results?
(a) 0.2000m (b) 0.200m (d) 0.20m (d) 0.2m
2.
Forces are applied to a rigid body. The forces all act in the same plane.
In which diagram is
the body in equilibrium?
3.
An athlete makes a long jump and follows a projectile motion. Air
resistance is
negligible.
Which one of the following statements is true about the athlete?
(a) The athlete has a constant horizontal and vertical velocities.
(b) The athlete has a constant horizontal velocity and constant
downward acceleration.
(c) The athlete has a constant upward acceleration followed by a constant
downward
acceleration.
(d) The athlete has a constant upward velocity followed by a constant
downward velocity.
4. At Kulekhani-I Hydro-power station, water flows from
Indra Sarowar into the turbines that are a vertical
distance of 550 m below the lake, as shown in the
diagram. Generally, 780 000 kg of water flows
into the
turbines every minute. The turbines have the
efficiency of 85%. What is the output power of the
turbines?
(a) 71 MW (b) 60MW (c) 4.2 GW (d) 3.6 GW
5.
Graphs of stress-strain for four different materials are shown below.
Which graph
represents the stiffest material?
6. A boy walks towards a stationary plane mirror at a speed of 1.2 ms-1
. What is the relative
speed of approach of the boy and his image?
(a) zero (b) 1.2 ms-1 (c) 2.4 ms-1 (d) 1.44 ms-1
7. The critical angle between an equilateral prism and air is 45o
. What happens to the incident
ray perpendicular to the refracting surface?
(a) It is reflected totally from the second surface and emerges
perpendicular from the third.
surface.
(b) It gets reflected from second and third surfaces and emerges from the
first surface
(c) It keeps reflecting from all the three sides of the prism and never
emerges out.
(d) After deviation, it gets refracted from the second surface.
8. In the formation of a rainbow, the light from the sun on water droplets
undergoes which of
the following phenomenonphenomena?
(a) dispersion only (b) only total reflection.
(c) dispersion and total internal reflection (d) scattering
9. In what unit is the power of lens measured?
(a) watt (b) metre (c) dioptre (d) Hertz
10.
A piece of wire of resistance R is bent through 180o
at mid-point and the two halves are
twisted together. What is the resistance of the wire thus formed?
(a) R/4 (b) R/2 (c) R (d) 2R
11. What are the elementary particles with half spin called?
(a) quarks (b) bosons (c) fermions (d) hadrons
Group 'B'
Answer the following questions. (8 × 5 = 40)
1. (a) State the law of conservation of momentum. [2]
(b) A jumbo jet of mass 4 x105 kg travelling at a speed of 5000 m/s lands
on the airport. It
takes 2 minutes to come to rest. Calculate the average force applied by
the ground on the aeroplane. [2]
(c) After landing the aeroplane's momentum becomes zero. Explain how the
law of
conservation holds here. [1]
OR
(a) State Hook’s law. [2]
(b) The walls of the tyres on a car are made of a rubber
compound. The variation with stress of the strain of a
specimen of this rubber compound is shown in Fig. 1.2.
As the car moves, the walls of the tyres end and straighten
continuously. Use Fig. 1.2 to explain why the walls of the
tyres become warm. [3]
2(b). [1]
3.
(a) Sate any three properties of an ideal gas as assumed by the kinetic
theory of gas. [3]
4. (a) Define temperature gradient in an object.
(b) An electric kitchen range has a total wall area of 1.40 m2 and is
insulted with a layer
5. Figure 5.1 shows a ray of light is entering and
OR
(a) Define ‘concave mirror’ and state on daily application of it. [2]
6.
(a) Sketch an electric field pattern around two identical negative point
charges shown
(b) Obtain an equation, in terms of Q and r, for the field strength at
point X due to two
7. (a) Define capacitance of a parallel plate capacitor and state one
application of it in
(b) Three capacitors each of 1000μF are connected in an electric circuit
as shown
answer. [2]
Give long answer to the following questions. (3 × 8 = 24)
10. A boy is operating a remote-controlled toy car on a horizontal circular
track, as
The track has a radius of 1·8 m and the car travels around the track with
a
The gravitational potential at point A in the orbit of Juno is -1·70 ×
109
(b) At point B, Juno is 1·69 × 108 m from the centre of Jupiter. If the
mass if
11. (a) Explain how Rutherford’s -scattering experiment suggested that
the nucleus of an
2. (a) What is meant by specific latent heat of vaporization of water =
2.26MJkg−1
? [1]
(b) A 1.0kW kettle contains 500g of boiling water. Calculate the time
needed to
evaporate all the water in the kettle. (Specific latent heat of
vaporization of
water = 2.26MJkg−1
). [3]
(c) Explain why the actual time needed is a little longer than the time
calculated in
(b) A student needed to use the ideal gas for a certain experiment. But,
the ideal gas does
not exist. Suggest what two different things this student could do to
solve his problem.
[2]
of fiber glass that has a temperature of 175oC and its outside surface is
35 oC. The
fiber glass has a thermal conductivity of 0.040 Wm-1K-1
. Calculate the rate of flow of
heat through the insulation, assuming the fibre as a flat slab of area of
1.40 m2
. [3]
(c) How might the rate of conduction be affected if the fiber absorbs
moisture? Justify your
answer. [1]
emerging through a part of a convex lens.
(i) Define ‘convex lens', and state one daily
application of it. [2]
(i) Explain why this lens is also called
converging lens? [1]
(ii) Calculate the refractive index of the material
of the lens shown in the figure.
[2]
(b) A certain projector uses a concave mirror for
projecting an object’s image on a screen. It
produces an image that is 5 times bigger than
the object and the screen is 5m away from the
mirror as shown in Fig. 5.2.
(i) Give reason why is the image larger than the
object? [1]
(ii) Calculate the focal length of the mirror.
[2]
below. [2]
charges shown in shown in Fig. 6.1 [3]
electric circuit. [2]
below.
(i) Identify the type of combination shown in Fig. 7.1, and calculate the
effective
capacitance of the combination. [1+2]
8.
(a) What is it meant by power of a heater is 2 kW? [1]
(b) Calculate the resistance of the above mentioned heater when it is
connected to 220V
source. [2]
(c) Suggest what changes must be done to the heater so that it gives more
heat. Justify your
Group 'C'
9. A box at rest is accelerated by a rope attached with a motor as shown
in the Fig
2.1. The velocity-time graph given below shows the pattern of its motion
for 20 s.
(a) If the box is pulled with constant unbalanced force 10N. Show that the
initial
acceleration of the box is 2.5 ms-2
, and calculate its mass. [2+1]
(b) After 2.0 second the box is being pulled by a constant force 12 N.
Determine the size of frictional forces acting on the box at this time.
[2]
(c) Determine the distance of the box travels along the ground at 8.0s.
[3]
shown in Figure.
constant speed.
(i) Explain why the car is accelerating, even though it is travelling at a
constant
speed. [2]
(ii) The car has a mass of 0·50 kg. The boy now increases the speed of the
car
to 6·0 m s -1
. The total radial friction between the car and the track has a
maximum value of 7.0 N.
Show by calculation that the car cannot continue to travel in a circular
path. [3]
(iii) The car is now placed on a track, which includes a raised section.
This is
shown in Figure 10.2
The raised section of the track can
be considered as the arc of a circle,
which has radius r of 0·85 m. The
car will lose contact with the raised
section of track if its speed is
greater than vmax. Show that vmax
is given by the relationship vmax
= √𝑟𝑔 . [3]
OR
Juno is a NASA orbiter with a
mission to survey Jupiter. It is
in an elliptical orbit around
Jupiter as shown in the figure
below.
J kg-1
.
(a) State what is meant by a gravitational potential at point A is -1·70 ×
109
J
kg-1
. [2]
Jupiter is 1.90 1027 kg, calculate the gravitational potential at point
B.
[3]
(c) The mass of Juno is 1·6 × 103 kg. Determine the change in
gravitational potential
energy if Juno moves from Point A to Point B. [3]
atom is very small, very dense and positively charged. [3]
(b) Considering that the -particles carry average kinetic energy of 2.00
x 1010 J,
calculate the maximum size of the gold nucleus. [Atomic number of gold is
79 and
e= 1.60 x 10-19C] [3]
(c) Explain why the radius of the gold nucleus must be much smaller than
the value
calculated in 11(b) above.