11th Physics - Book Back Answers - Unit 10 - English Medium Guides

 

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Tamil Nadu Board 11th Standard Physics - Unit 10: Book Back Answers and Solutions

    This post covers the book back answers and solutions for Unit 10 – Physics from the Tamil Nadu State Board 11th Standard Physics textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.

    We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.

    By going through this material, you’ll gain a strong understanding of Physics Unit 10 along with the corresponding book back questions and answers (PDF format).

Question Types Covered:

• 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following 
• 2 Mark Questions: Answer briefly 
• 3, 4, and 5 Mark Questions: Answer in detail

All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.

All the best, Class 11 students! Prepare well and aim for top scores. Thank you!

Unit 10:Oscillations

I. Multiple Choice Questions

1. In a simple harmonic oscillation, the acceleration against displacement for one complete oscillation will be (model NSEP 2000-01)
a) an ellipse 
b) a circle
c) a parabola 
d) a straight line
Answer Key:
d) a straight line

2. A particle executing SHM crosses points A and B with the same velocity. Having taken 3 s in passing from A to B, it returns to B after another 3 s. The time period is
a) 15 s 
b) 6 s
c) 12 s 
d) 9 s
Answer Key:
c) 12 s 

3. The length of a second’s pendulum on the surface of the Earth is 0.9 m. The length of the same pendulum on surface of planet X such that the acceleration of the planet X is n times greater than the Earth is
a) 0.9n 
b) $\frac{0.9}{\mathrm{n}}\mathrm{m}$

c) 0.9n²m

d) $\frac{0.9}{{\mathrm{n}}^2}$
Answer Key:
a) 0.9n 

4. A simple pendulum is suspended from the roof of a school bus which moves in a horizontal direction with an acceleration a, then the time period is
a) $\mathrm{T}\propto \frac{1}{{\mathrm{g}}^2+{\mathrm{a}}^2}$
b) $\mathrm{T}\propto \sqrt{\frac{1}{{\mathrm{g}}^2+{\mathrm{a}}^2}}$
c) $\mathrm{T}\propto \sqrt{{\mathrm{g}}^2+{\mathrm{a}}^2}$
d) $\mathrm{T}\propto ({\mathrm{g}}^2+{\mathrm{a}}^2)$
Answer Key:
b) $\mathrm{T}\propto \sqrt{\frac{1}{{\mathrm{g}}^2+{\mathrm{a}}^2}}$

5. Two bodies A and B whose masses are in the ratio 1:2 are suspended from two separate massless springs of force constants k_A  and k_A  respectively. If the two bodies oscillate vertically such that their maximum velocities are in the ratio 1:2, the ratio of the amplitude A to that of B is
a) $\sqrt{\frac{{\mathrm{k}}_{\mathbf{B}}}{2{\mathrm{k}}_{\mathrm{A}}}}$
b) $\sqrt{\frac{{\mathrm{k}}_{\mathbf{B}}}{8{\mathrm{k}}_{\mathrm{A}}}}$
c) $\sqrt{\frac{{\mathrm{2k}}_{\mathbf{B}}}{{\mathrm{k}}_{\mathrm{A}}}}$
d) $\sqrt{\frac{{\mathrm{8k}}_{\mathbf{B}}}{{\mathrm{k}}_{\mathrm{A}}}}$
Answer Key:
b) $\sqrt{\frac{{\mathrm{k}}_{\mathbf{B}}}{8{\mathrm{k}}_{\mathrm{A}}}}$

6. A spring is connected to a mass mm suspended from it and its time period for vertical oscillation is T. The spring is now cut into two equal halves and the same mass is suspended from one of the halves. The period of vertical oscillation is
a) $\mathrm{T}\text{'} = \sqrt{2}\mathrm{T}$
b) $\mathrm{T}\text{'} =\frac{\mathrm{T}}{\sqrt{2}}$
c) $\mathrm{T}\text{'} = \sqrt{2\mathrm{T}}$
d) $\mathrm{T}\text{'} =\sqrt{\frac{\mathrm{T}}{2}}$
Answer Key:
b) $\mathrm{T}\text{'} =\frac{\mathrm{T}}{\sqrt{2}}$

7. The displacement of a simple harmonic motion is given by y(t) = A sin (ωt + ϕ) where A is amplitude of the oscillation, ω is the angular frequency and ϕ is the phase. Let the amplitude of the oscillation be 8 cm and the time period of the oscillation is 24 s. If the displacement at initial time(t=0 s) is 4 cm, then the displacement at t = 6 s is
(a) 8 cm
(b) 4 cm
(c) $4 \sqrt{3}$ cm
(d) 8$\sqrt{3}$ cm
Answer Key:
(d) 8$\sqrt{3}$ cm

8. A simple pendulum has a time period T₁. When its point of suspension is  moved vertically upwards according as y = k t², where y is vertical distance covered and k = 1ms⁻², its time period becomes T₂. Then, T is $\frac{{\mathrm{T}}_1^2}{{\mathrm{T}}_2^{\mathrm{2 }}}$ (g = 10  ms⁻²) (IIT 2005)
a) $\frac{5}{6}$
b) $\frac{11}{10}$
c) $\frac{6}{5}$
d) $\frac{5}{4}$
Answer Key:
c) $\frac{6}{5}$

9. An ideal spring of spring constant k, is suspended from the ceiling of a room and a block of mass M is fastened to its lower end. If the block is released when the spring is un-stretched, then the maximum extension in the spring is (IIT 2002)
a) $4\frac{\mathrm{Mg}}{\mathrm{k}}$
b) $\frac{\mathrm{Mg}}{\mathrm{k}}$
c) $2\frac{\mathrm{Mg}}{\mathrm{k}}$
d) $\frac{\mathrm{Mg}}{\mathrm{2k}}$
Answer Key:
c) $2\frac{\mathrm{Mg}}{\mathrm{k}}$

10. A pendulum is hung in a very high building oscillates to and fro motion freely like a simple harmonic oscillator. If the acceleration of the bob is 16 ms−2 at a distance of 4 m from the mean position, then the time period is (NEET 2018 model)
a) 2 s 
b) 1 s
c) 2πs 
(d) πs
Answer Key:
a) 2 s 

11. A hollow sphere is filled with water. It is hung by a long thread. As the water flows out of a hole at the bottom, the period of oscillation will
a) first increase and then decrease
b) first decrease and then increase
c) increase continuously
d) decrease continuously
Answer Key:
a) first increase and then decrease

12. The damping force on an oscillator is directly proportional to the velocity. The units of the constant of proportionality are (AIPMT 2012)
a) kg ms⁻¹
b) kg ms⁻²
c) kg s⁻¹ 
d) kg s
Answer Key:
c) kg s⁻¹

13. Let the total energy of a particle executing simple harmonic motion with angular frequency is 1 rad s⁻¹ is 0.256 J. If the displacement of the particle at time t =$\frac{\mathrm{ \pi }}{2}$  is 8$\sqrt{2}$  cm then the amplitude of
motion is
a) 8 cm 
b) 16 cm
c) 32 cm
d) 64 cm
Answer Key:
b) 16 cm

14. A particle executes simple harmonic motion and displacement y at time t₀, 2t₀ and 3t₀ are A, B and C, respectively. Then the value of $\frac{\mathrm{A}+\mathrm{B}}{2\mathrm{B}}$
(a) cos ωt₀ 
(b) cos 2ωt₀
(c) cos 3ωt₀
(d) 1
Answer Key:
(b) cos 2ωt₀

15. A mass of 3 kg is attached at the end of a spring moves with simple harmonic motion on a horizontal frictionless table with time period 2π and with amplitude of 2m, then the maximum fore exerted on the spring is
(a) 1.5 N
 (b) 3 N
(c) 6 N
(d) 12 N
Answer Key:
(c) 6 N

 

II. Short Answer Questions

11th physics

III. Long Answer Questions

11th Physics

IV. Exercise

11th Physics