# ASVAB Science Physics Practice Test 2

Question – 1

1. A spring scale can read maximum weight of 150 N. If a block of wood stretches the spring scale to its full limit, what would be the mass of the block of wood?

• A. 14.7 kg

• B. 15.3 kg

• C. 9.8 kg

• D. 0.065 kg

• E. 12.56 kg

• Answer Explanation: Since the spring scale is stretched fully, the weight it would measure is 150 N. Weight of block is given asw=mg150 = m X 9.8m= 150/9.8m=15.3 kgTherefore, B is the correct answer option.

Question – 2

2. An object A of mass 40 kg at 60o C has internal energy of 4000 J. If it is kept in contact with another object B of mass 40 kg at 65o C having internal energy 4500 J, then which of the following statements is true regarding heat transfer? (Assume boundary of contact can allow heat transfer to take place)

• A. Heat will flow from A to B

• B. Heat will flow from B to A

• C. No heat will flow between the objects A and B

• D. Temperature of A decreases

• E. Temperature of B increases

• Answer Explanation:Heat always flows from a hot body to a cooler body. In other words, heat flows from a body at a higher temperature to a body at a lower temperature. If an object A, at 60o C is kept in contact with another object B, at 65o C, then this means that object A is at lower temperature than that of object B. Hence, heat will flow from B to A. Also, as the heat is transferred from B to A, temperature of B will reduce but temperature of A will increase to reach thermal equilibrium. Thus, B is the correct answer option and A, C, D and E are incorrect answer options.

Question – 3

3. A car of mass 490 kg is moving along a straight path with a velocity of 30 m/s. If the driver suddenly accelerates the car to a velocity of 40 m/s, what is the work done by the car?

• A. 150120 J

• B. 156045 J

• C. 174560 J

• D. 171500 J

• E. 4900 J

• Answer Explanation:W = KE2 – KE1W = 1/2 m (v22 – v12)W = 1/2 X 490 X (402 – 302) Or W = 171500 JTherefore, D is the correct answer option.

Question – 4

4. If the wavelength of a photon is , what would be its frequency?

• A. 3 X 1015 Hz

• B. 3 X 1014 Hz

• C. 3 X 108 Hz

• D. 3 X 1016 Hz

• E. 1015 Hz

• Answer Explanation:Speed of a photon is given as c = ????As every photon travels with the speed of light, c = 3 X 108 m/s.3 X 108 = ?? X 10-7?? = 3 X 1015 HzThus, A is the correct answer option.

Question – 5

5. A rain drop takes 50 seconds to reach the earth’s surface which is at 2 km from the clouds. What is the average velocity of the rain drop?

• A. 96 km/h

• B. 150 km/h

• C. 19.6 km/h

• D. 490 km/h

• E. 144 km/h

• Answer Explanation:Since time is given in seconds we need to convert it into hours hence,Total time taken = 50s = (50/3600)hTherefore, Average velocity = 2 km/(50/3600)hAverage velocity = 2 X 3600/50 km/h = 144 km/hE is the correct answer option.

Question – 6

6. How many electronic charges comprise a coulomb of charge?

• A. 6 X 1018

• B. 1018

• C. 2 X 1018

• D. 2 X 1019

• E. 5 X 1015

• Answer Explanation:Charge is given as Q= ne1= n X 1.6 X 10-19 Or n = 6.25 X 1018Therefore number of electronic charges that make one coulomb of charge is 6 X 1018. Therefore, A is the correct answer option.

Question – 7

7. Speed of light in a medium is 1.6 X 107 m/s. What is the refractive index of the medium?

• A. 0.53

• B. 1.87

• C. 17.65

• D. 18.75

• E. 18.23

• Answer Explanation:Refractive index of any medium is the ratio of speed of light in vacuum to the speed of light in that medium. It is given as?? = c/v Or ?? = 3 X 108 / 1.6 X 107?? = 18.75Hence, refractive index of the medium is 18.75. Therefore, D is the correct answer option.

Question – 8

8. A hollow sphere and a solid sphere have the same mass and the same radius. Which of the following is the correct statement?

• A. Moment of inertia of the hollow sphere is same as that of the solid sphere

• B. Moment of inertia of the solid sphere is more than that of the hollow sphere

• C. Moment of inertia of the solid sphere is less than that of the hollow sphere

• D. Moment of inertia does not depends on the mass and the radius

• E. Not enough data is provided to get the result

• Answer Explanation:Moment of inertia of the solid sphere is given asIs = 2/5 MR2 —— (1)Moment of inertia of the hollow sphere is given asIH = 2/3 MR2 —— (2)Now, expressing equation 2 in form of 1 we getIH = 2/3 X 5/2 X 2/5 MR2 Or IH = 5/3 IsHence, moment of inertia of hollow sphere is greater than that of the solid sphere. Hence, C is the correct answer option and E is an incorrect option.

Question – 9

9. What is the dimensional formula of torque?

• A. MLT-2

• B. MT-2

• C. ML2T-2

• D. MLT-1

• E. ML3T-2

• Answer Explanation:?? = r X FSince dimensional formula of force is MLT-2 and that of displacement is hence, dimensional formula of torque becomesMLT-2 X L Or ML2T-2Therefore, C is the correct answer option.

Question – 10

10. What would be the pressure at a depth of 5 m below the surface of water? (Take density of water = 1000 kg/m3 and acceleration due to gravity =9.8 m/s2)

• A. 45000 Pa

• B. 50000 Pa

• C. 49000 Pa

• D. 9800 Pa

• E. 5000 Pa

• Answer Explanation:Pressure due to fluid is given asP = ??gh Or P = 1000 X 9.8 X 5P = 49000 PaHence, C is the correct answer option.

Question – 11

11. 110 N of force is required to move an object of mass 23 kg along a horizontal surface. When the object is in motion, 70 N of force is required to keep it in motion. The coefficient of static friction is ________.

• A. 0.488

• B. 0.31

• C. 0.23

• D. 0.488

• E. 0.26

• Answer Explanation:FR = ??sRR = 225.4N (since, R = mg)Therefore, 110 = ??s X 225.4 or ??s = 0.488.

Question – 12

12. Displacement of a particle in SHM is given as x(t) = 2.3 sin (314t)cm. What is the amplitude and frequency of oscillation of the particle?

• A. 2.6 cm

• B. 2.8 cm

• C. 2.3 cm

• D. 2.6 cm

• E. 3.14 cm

• Answer Explanation:General expression for displacement of a body in SHM is given as x(t) = A sin (??t)Here, x(t) = 2.3 sin (314t)cmComparing the equations we get A = 2.3 cm.

Question – 13

13. Which of the following do not require any medium to propagate?

• A. Sound waves

• B. Seismic waves

• C. Tides

• D. Light waves

• E. Waves on the surface of water

• Answer Explanation:Light waves do not require any medium to propagate. For example, light waves coming from the Sun travel most of the distance through the outer space that is devoid of any medium. Therefore, D is the correct answer option.

Question – 14

I. Temperature may or may not remain constantII. Temperature should remain constantIII. All external conditions may or may not remain constantIV. All external conditions should remain constant

• A. Both II and III

• B. Both I and IV

• C. Both II and IV

• D. Both I and III

• E. All four

• Answer Explanation:Ohm’s law is defined as: if the temperature and all external conditions are kept constant then the current through a conductor is directly proportional to the potential difference across it. If the temperature or external conditions change, then the current through the conductor varies accordingly. Hence, both the temperature and the external conditions have to remain constant for Ohm’s law to be valid. Thus, C is the correct answer option.

Question – 15

15. A straight wire of length 10 cm is bent into circular form. What is the current flowing through the wire if the magnetic dipole moment of the wire is 1.5 X 10-3 Am2 ?

• A. 2.875 A

• B. 0.875 A

• C. 1.5 A

• D. 1.875 A

• E. 3.875 A