MODEL QUESTION PAPER 5

Download Tamil Nadu 11th Standard Physics question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.

Questions:

Multiple Choice Question

8 x 1 = 8

The centre of mass of a solid cone along the line from the centre of the base to the vertex is at ___________.

(a)

one-fourth of the height

(b)

one-third of the height

(c)

one-fifth of the height

(d)

none of these

A bullet is fired from a rifle. If the rifle recoils freely the K.E of the rifle as compared to that of bullet is ______________.

(a)

greater

(b)

equal

(c)

lesser

(d)

none of the above

A body of mass 30 kg climbs on a rope. The boy climbs up with an acceleration of 5 ms^-2What is the tension of a rope?

(a)

250 N

(b)

540 N

(c)

312 N

(d)

444 N

When a mass is rotating in a plane about a fixed point, its angular momentum is directed along

(a)

a line perpendicular to the plane of rotation

(b)

the line making an angle of 45^o to the plane of rotation

(c)

the radius

(d)

tangent to the path

The angle between A i +j and B = i - j is ______________.

(a)

45°

(b)

90°

(c)

-45°

(d)

180°

What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop?

(a)

\(\sqrt{2gR}\)

(b)

\(\sqrt{3gR}\)

(c)

\(\sqrt{5gR}\)

(d)

\(\sqrt{gR}\)

Identify the unit vector in the following?

(a)

\(\hat { i } +\hat { j } \)

(b)

\(\frac { \hat { i } }{ \sqrt { 2 } } \)

(c)

\(\hat { k } -\frac { \hat { j } }{ \sqrt { 2 } } \)

(d)

\(\frac { \hat { i } +\hat { j } }{ \sqrt { 2 } } \)

Which of the following has the highest number of significant figures?

(a)

0.007 m²

(b)

2.64\(\times\)10²⁴kg

(c)

0.0006032 m²

(d)

6.3200 J

Generic 2

8 x 2 = 16

If the Earth’s pull on the Moon suddenly disappears, what will happen to the Moon?

10.

Write down the moment of inertia of a disc of radius R and mass m about an axis in its plane at a distance R/2 from its centre

11.

Which is the greatest force among the three force \(\vec { { F }_{ 1 } } ,\vec { { F }_{ 2 } } ,\vec { { F }_{ 3 } } \), shown below:

12.

Give examples where the centre of mass coincides with the geometrical centre of the body.

13.

When is the exchange of energy maximum during an elastic collision?

14.

A beam of metal has length, breadth and height as 4m, 3m and 5m respectively. Then what will be the volume of the metal beam? Express the result in SI unit system.

15.

What are the factors the horizontal range directly depends?

16.

How will you measure the diameter of the Moon using parallax method?

Generic 3

5 x 3 = 15

17.

How will you prove that Earth itself is spinning?

18.

A jester in a circus is standing with his arms extended on a turn table rotating with angular velocity \(\omega\). He brings his arms closer to his body so that his moment of inertia is reduced to one third of the original value. Find his new angular velocity. [Given: There is no external torque on the turn table in the given situation.]

19.

The velocity of three particles A, B, C are given below. Which particle travels at the greatest speed?
\(\vec {v_A}=3\hat i+5\hat j+2\hat k\)
\(\vec {V_B}=\hat i+2\hat j+3\hat k\)
\(\vec{V_C}=5\hat i+3\hat j+4\hat k\)

20.

A bomb of mass 30 kg, initially at rest explodes into three pieces of masses. m₁ = m₂= 20 kg. If the kinetic energy of two pieces (m₁ = m₂) is 400 J. Calculate the kinetic energy of the third piece.

21.

Define the following
a) Coefficient of restitution

Visit QB365-SLMS - https://www.qb365.in/slms/

Answers Key:

Multiple Choice Question

8 x 1 = 8

(a)
one-fourth of the height

(d)
444 N

(a)
a line perpendicular to the plane of rotation

(b)
90°

Radius =R
\(v_{1}^{2}-v_{2}^{2}=4 g R\)
\(\text { Tension } T_{2}=\frac{m v_{2}^{2}}{R_{2}}-m g\)
\(\text {To find minimum speed, let } T_{2}=0\)
\(0 =\frac{m v_{2}^{2}}{R}-m g \)
\(\frac{m v^{2}}{R} =m g \)
\(v_{2}^{2}=R g \ v_{2} =\sqrt{g R} \)
\(\text { sub (2) in the eqn (1) we get }\)
\(v_{1}^{2}-(\sqrt{g R})^{2} =4 g R \)
\(v_{1}^{2}-g R =4 g R \)
\(v_{1}^{2} =4 g R+g R \)
\(=5 g R \)
\(v_{1} =\sqrt{5 g R} \)

Unit vector specifies only direction
\(\hat{A}=\frac{\vec{A}}{|\vec{A}|} \)
\(\therefore \hat{i}+\hat{j}=\frac{\hat{l}+\hat{j}}{|\hat{l}+\hat{j}|} \)
\(\hat{i} \text { and } \hat{j} \text { are orthogonal components of vectors. }\)
\(\therefore|\hat{i}+\hat{j}|=\sqrt{1^{2}+1^{2}}=\sqrt{1+1}=\sqrt{2}\)

The number of significant figures of 6.3200 J is 5

Generic 2

8 x 2 = 16

Moon will start to move in spiral path towards the earth and it may hit on the surface of the Earth.

10.

\(\frac{1}{2}\)MR²

11.

Force is a vector and magnitude of the vector is represented by the length of the vector. Here \(\vec { { F }_{ 1 } } \) has greater length compared to other two. So \(\vec { { F }_{ 1 } } \) is largest of the three.

12.

For symmetrically shaped bodies of uniform composition (Eg: spheres, cylinders, rectangular solids), the centre of mass is located at the geometrical centre of the body.

13.

Energy exchange will be maximum if the two colliding bodies are of equal masses.

14.

Volume = length\(\times\)breadth\(\times\)height
SI unit of volume (v) = m\(\times\)m\(\times\)m = m³
SI unit of length (I) = 4m
SI unit of breadth (b)= 3m
SI unit of height (h) = 5m
Volume (v) = I\(\times\)b\(\times\)h
= 4\(\times\)3\(\times\)5 = 60m³

15.

(i) Initial speed (u)
(ii) The sine of angle of projection (\(\theta\)).
(iii) It inversely depends on acceleration due to gravity 'g'.

16.

C is the centre of the Earth. A and B are two diametrically opposite places on the surface of the Earth. From A and B, the parallaxes θ₁and θ₂ respectively of Moon M with respect to some distant star are determined with the help of an astronomical telescope. Thus, the total parallax of the Moon subtended on Earth.
\(\angle AMB=\theta_1+ \theta_2=\theta\)
If θ is measured in radians, then
\(\theta=\frac{A B}{A M} ; A M \approx M C \quad {\theta}=\frac{A B}{M C} \text { or } M C=\frac{A B}{\theta}\)
Knowing the values of AB and θ, we can calculate the distance MC of Moon from the Earth.

Generic 3

5 x 3 = 15

17.

Due to Earth's spinning motion, the stars in sky appear to move in circular motion about the pole star.

18.

Let the moment of inertia of the jester with his arms extended be I. As there is no external torque acting on the jester and the turn table, his total angular momentum is conserved. We can write the equation,
\(I_i \omega_i=I_f \omega_f\)
\(I \omega=\frac{1}{3} I\omega_f\) \(\because (I_f=\frac{1}{3}I)\)
\(\omega_f=3\omega\)
The above result tells that the final angular velocity is three times that of initial angular velocity.

19.

We know that speed is the magnitude of the velocity vector. Hence,
Speed of A = \(|\vec{V_A}|=\sqrt{(3)^2+(-5)^2+(2)^2}=\sqrt{9+25+4}=\sqrt{48}ms^{-1}\)
Speed of B = \(\vec{V_B}=\sqrt{(1)^2+(2)^2+(3)^2}=\sqrt{1+4+9}=\sqrt{14}ms^{-1}\)
Spedd of C = \(\vec{V_C}=\sqrt{(5)^2+(3)^2+(4)^2}=\sqrt{25+9+16}=\sqrt{50}ms^{-1}\)
The particle C has the greatest speed.
\(\sqrt{50}>\sqrt{38}>\sqrt{14}\)

20.

Total mass = 30 kg m₁ = m₂ = 20 kg
Mass of a third piece, m₃ =Total mass - m₁ and m₂= 30 kg - 20 kg
Kinetic energy of m₁ and m₂ = 400 J
Kinetic energy of m₃ =?
\({ V }_{ 3 }=\sqrt { \frac { 2\left( { E }_{ 1 }+{ E }_{ 2 } \right) }{ \left( { m }_{ 1 }+{ m }_{ 2 } \right) } } \)
\({ V }_{ 3 }=\sqrt { \frac { 2\times 400 }{ 20 } } \)
\({ V }_{ 3 }=\sqrt { \frac { 800 }{ 20 } } \)\(=\sqrt { 40 } \)
V₃ = 6.32 ms^-2
Let V₃be the speed of the Kg mass

21.

(a) Coefficient of restitution
It is defined as the ratio of velocity of separation (relative velocity) after collision to the velocity of approach (relative velocity) before collision.
\(e=\frac{v_2-v_1}{u_1-u_2}\)