Question – 1

1. What would be the work done by a force to stop a car of mass 500 kg moving with a velocity of 24 m/s?

- A. 144000 J
- B. 100000 J
- C. 12000 J
- D. 6000 J
- E. 169000 J
- Answer:A
- Answer Explanation:W = KE
_{2}– KE_{1}Or W = 1/2 m(v^{2}– u^{2})W = 1/2 X 500 X (0^{2}– 24^{2})Or W = -144000 JNegative sign is because work is done in stopping the car (retardation). Same would be coming in positive if the work is done in moving the car. Hence, A is the correct answer option.

Question – 2

2. A car starts from a point A at 9 AM and reaches point B at 11 AM. If A and B are separated by 100 km and the car is moving with uniform speed, what is the speed of the car for the entire travel in m/s?

- A. 15.7 m/s
- B. 13.9 m/s
- C. 11.3 m/s
- D. 10.4 m/s
- E. 14.5 m/s
- Answer:B
- Answer Explanation:Speed is given as v = d/tv = 100/2 or v = 50 km/hConvert hours into seconds and km into m.50 km/h = 50 X 1000/3600 m/sor 50 km/h = 13.9 m/sHence, B is the correct answer option.

Question – 3

3. A rotor with uniform angular speed of 210 s-1 needs a torque of 250 Nm from an engine. What would be the power of the engine required for the torque?

- A. 54500 W
- B. 52500 W
- C. 34600 W
- D. 1.19 W
- E. None of the above choices
- Answer:B
- Answer Explanation:Power associated with torque is given as P = ?? ??P = 250 X 210Or P = 52500 WHence, B is the correct answer option.

Question – 4

4. What would be the number of electric lines of forces coming out of a unit charge?

- A. 5.5 X 10
^{7} - B. 8.5 X 10
^{-7} - C. 2.15 X 10
^{7} - D. 1.11 X 10
^{-5} - E. 1.81 X 10
^{-8} - Answer:E
- Answer Explanation:Electric lines of forces are nothing but electric flux lines. Electric flux originating from a charge is given as?? = Q/??
_{0}——-(1)?? = -(1.6 X 10^{-19}) / (8.85 X 10^{-12}) Or ?? = – 1.81 X 10^{-8}Negative sign signifies that the electric field lines for an electron are inwards rather than outwards. Neglecting the negative sign, number of electric lines of force becomes 1.81 X 10^{-8}. The result suggests that, electric flux for an electron is of a very minute quantity.Hence, E is the correct answer option.

Question – 5

5. A tuning fork vibrates with a frequency of 500 Hz. If the speed of sound in air is 343 m/s, what is the distance the sound travels when the tuning fork makes 100 oscillations?

- A. 34.3 m
- B. 50.4 m
- C. 5 m
- D. 76.8 m
- E. 68.6 m
- Answer:E
- Answer Explanation:v = ????343 = 500 X ?? Or ?? = 0.686 mThis is the distance which the sound travels in one oscillation. The distance traveled in 100 oscillations is d = 100 X 0.686 m Or d = 68.6 mHence, E is the correct answer option.

Question – 6

6. A force acting on a body of mass 10 kg changes its velocity from 3 m/s to 6.7 m/s in 20 seconds. What is the magnitude of the force applied on the body?

- A. 10 N
- B. 3.77 N
- C. 1.85 N
- D. 4.55 N
- E. 2.33 N
- Answer:C
- Answer Explanation:F = m(v-u)/tF= 10 X (6.7-3)/20Or F = 1.85 NHence, C is the correct answer option.

Question – 7

7. Which of the following is a unit of power?

- A. J
- B. Nm/s
- C. W/s
- D. W/s
- E. None of the above choices
- Answer:B
- Answer Explanation:P = W/t and W = F.dSI unit of force (F) is N, displacement (d) is m and time (t) is s.Therefore P = Nm/s Or, P = Nm/sHence, B is the correct answer option.

Question – 8

Which of the following statement(s) is true in accordance to the given figure?

- A. 2
- B. 1
- C. 3
- D. Both 1 and 2
- E. Both 2 and 3
- Answer:A
- Answer Explanation:Force experienced by the beta particle is given as F = qvB sin ??F = 1.6 X 10
^{-19}X 10^{4}X 0.01 X sin 90^{o}F = 1.6 X 10^{-17}X 1 NF = 1.6 X 10^{-17}NHence, B is the correct answer option.

Question – 9

9. What is the buoyant force exerted on a 20 cm^{3} block of iron submerged completely inside water?

- A. 0.234 N
- B. 0.111 N
- C. 2.289 N
- D. 1.34 N
- E. 0.196 N
- Answer:E
- Answer Explanation:Buoyant force is given as F
_{B}= ??gVAs the block is submerged completely, volume of water displaced is equal to the volume of the block = 20 cm^{3}.As the volume is given in cm^{3}we need to convert it into m^{3}.F_{B}= 1000 X 9.8 X 2 X 10^{-5}Or F_{B}= 0.196 NHence, E is the correct answer option.

Question – 10

10. A particle in SHM has a time period of 3 s and amplitude of 0.1 m. What is the displacement of the particle after 1 s?

- A. 0.011 m
- B. 0.23 m
- C. 0.087 m
- D. 0.754 m
- E. Zero
- Answer:C
- Answer Explanation:y(t) = Asin(2??/T)ty(1) = 0.1 X sin(2??/3)1y(1) = 0.1 X ???3/2 Or y(1) = 0.087 mHence, C is the correct answer option.

Question – 11

11. Which of the following consist of the highest energy photons?

- A. X-ray
- B. Visible light
- C. Infrared
- D. Radio waves
- E. Microwaves
- Answer:A
- Answer Explanation:All of the options given above are electromagnetic waves. They travel at 3 X 10
^{8}m/s. Radio waves have energy in order of 10^{-9}eV (electron-volt) to 10^{-6}eV. Microwaves have energy in order of 10^{-5}eV to 10^{-2}eV. Infrared have energy in order of 1 to 10^{-2}eV. Visible light have energy in order of 1.6 eV to 3.2 eV. X-rays have energy in order of 10^{2}to 10^{5}eV. Hence on comparing energies of all the electromagnetic waves given above, X-ray has the highest energy. Hence, A is the correct answer option.

Question – 12

12. Consider the figure given below for a system of two iron blocks connected with a common pulley. If the block A weighs 200 N, what would be the mass of the iron block B to keep the whole system in static equilibrium?

- A. 20.41 kg
- B. 15.57 kg
- C. 22.23 kg
- D. 34.45 kg
- E. 21.45 kg
- Answer:A
- Answer Explanation:As the whole system is in static equilibrium, there will be no motion in the blocks. In other words, weight of both the iron blocks should be the same.W = mg200 = m X 9.8Or m = 20.41 kgTherefore, A is the correct answer option.

Question – 13

13. Air is filled in a piston of capacity 100 liters at 313 K. At what temperature should the piston be heated so that volume increases to 120 liters for an isobaric process?

- A. 375.6 K
- B. 373 K
- C. 300.45 K
- D. 413.5 K
- E. 343.7 K
- Answer:A
- Answer Explanation:Isobaric process is carried out at a constant pressure. Since, pressure is constant here, we have to apply Charles’s law. According to Charles’ lawV
_{1}/ T_{1}= V_{2}/ T_{2}100/313 = 120/T_{2}Or T_{2}= 375.6 KHence, A is the correct answer option.

Question – 14

14. A spring balance measures the weight of a block of ice as 400 N. What is the mass of the block of ice?

- A. 34.65 kg
- B. 45.66 kg
- C. 40.82 kg
- D. 24.87 kg
- E. 76.56 kg
- Answer:C
- Answer Explanation:W = mg400 = m X 9.8Or m = 40.82 kgHence, C is the correct answer option.

Question – 15

15. What would be the power of a convex lens of focal length 10 cm?

- A. -0.2 dioptre
- B. -0.1 dioptre
- C. 10 dioptre
- D. -10 dioptre
- E. 0.05 dioptre
- Answer:C
- Answer Explanation:Power of a lens is given as P = 1/??Power of converging or convex lens is positive. Therefore P = 1/10 cmSI unit of power is m-1. Hence we need to convert the unit from cm
^{-1}to m^{-1}.P = 1/0.1 Or P = 10 m^{-1}There is another SI unit for power which is equivalent to m^{-1}and is known as dioptre.Therefore P = 10 dioptre. Hence, C is the correct answer option.