11th Physics - Book Back Answers - Unit 6 - English Medium Guides

 

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Tamil Nadu Board 11th Standard Physics - Unit 6: Book Back Answers and Solutions

    This post covers the book back answers and solutions for Unit 6 – 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 6 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 6:Gravitation

I. Multiple Choice Questions

1. The linear momentum and position vector of the planet is perpendicular to each other at
(a) perihelion and aphelion
(b) at all points
(c) only at perihelion
(d) no point
Answer Key:
(a) perihelion and aphelion

2. If the masses of the Earth and Sun suddenly double, the gravitational force between them will
(a) remain the same
(b) increase 2 times
(c) increase 4 times
(d) decrease 2 times
Answer Key:
(c) increase 4 times

3. A planet moving along an elliptical orbit is closest to the Sun at distance r₁ and farthest away at a distance of r₂. If v₁ and v₂ are linear speeds at these points respectively. Then the ratio $\frac{{\mathrm{v}}_1}{{\mathrm{v}}_2}$ is
 (NEET 2016)
(a) $\frac{{\mathrm{r}}_2}{{\mathrm{r}}_1}$
(b) 
(c) $\frac{{\mathrm{r}}_1}{{\mathrm{r}}_2}$
(d) 
Answer Key:
(a) $\frac{{\mathrm{r}}_2}{{\mathrm{r}}_1}$

4. The time period of a satellite orbiting Earth in a circular orbit is independent of.
(a) Radius of the orbit
(b) The mass of the satellite
(c) Both the mass of the satellite and radius of the orbit
(d) Neither the mass of the satellite nor the radius of its orbit
Answer Key:
(b) The mass of the satellite

5. If the distance between the Earth and Sun were to be doubled from its present value, the number of days in a year would be
(a) 64.5 
(b) 1032
(c) 182.5 
(d) 730
Answer Key:
(b) 1032

6. According to Kepler’s second law, the radial vector to a planet from the Sun sweeps out equal areas in equal intervals of time. This law is a consequence of
(a) conservation of linear momentum
(b) conservation of angular momentum
(c) conservation of energy
(d) conservation of kinetic energy
Answer Key:
(b) conservation of angular momentum

7. The gravitational potential energy of the Moon with respect to Earth is
(a) always positive
(b) always negative
(c) can be positive or negative
(d) always zero
Answer Key:
(b) always negative

8. The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and C are K_A, K_B and K_C respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure.Then  (NEET 2018)

(a) K_A > K_B >K_C

(b) K_B < K_A <K_C

(c) K_A < K_B <K_C

(d) K_B > K_A >K_C

Answer Key:
(a) K_A > K_B >K_C

9. The work done by the Sun’s gravitational force on the Earth is
(a) always zero
(b) always positive
(c) can be positive or negative
(d) always negative
Answer Key:
(c) can be positive or negative

10. If the mass and radius of the Earth are both doubled, then the acceleration due to gravity g'
(a) remains same
(b) $\frac{\mathrm{g}}{2}$
(c) 2 g 
(d) 4 g
Answer Key:
(b)  $\frac{\mathrm{g}}{2}$

11. The magnitude of the Sun’s gravitational field as experienced by Earth is
(a) same over the year
(b) decreases in the month of January and increases in the month of July
(c) decreases in the month of July and increases in the month of January
(d) increases during day time and decreases during night time.
Answer Key:
(c) decreases in the month of July and increases in the month of January

12. If a person moves from Chennai to Trichy, his weight
(a) increases
(b) decreases
(c) remains same
(d) increases and then decreases
Answer Key:
(b) decreases

13. An object of mass 10 kg is hanging on a spring scale which is attached to the roof of a lift. If the lift is in free fall, the reading in the spring scale is
(a) 98 N 
(b) zero
(c) 49 N 
(d) 9.8 N
Answer Key:
(b) zero

14. If the acceleration due to gravity becomes 4 times its original value, then escape speed
(a) remains same
(b) 2 times of original value
(c) becomes halved
(d) 4 times of original value
Answer Key:
(b) 2 times of original value

15. The kinetic energy of the satellite orbiting around the Earth is
(a) equal to potential energy
(b) less than potential energy
(c) greater than kinetic energy
(d) zero
Answer Key:
(b) less than potential energy

II. Short Answer Questions

11th physics

III. Long Answer Questions

11th Physics

IV. Exercise

11th Physics