# Essential guide to scientific principles

Published: Published Date - 11:45 PM, Sun - 11 September 22

These practice questions focusing on general science will aid aspirants to prepare better for the State government recruitment examinations.

**1. The centripetal force and centrifugal force are ______:**

a) Equal in magnitude and have same direction

b) Unequal in magnitude and have same direction

c) Equal in magnitude and have opposite direction

d) Unequal in magnitude and have opposite direction

**Ans**: c

**Explanation**: The centripetal force and centrifugal force are equal in magnitude and have opposite direction. Centrifugal force can be regarded as the reaction of centripetal force.

**2. The dot product of two vectors A and B is equal to the product of magnitude of A and B and __________?**

a) Cosine of the largest angle between them

b) Sine of the largest angle between them

c) Cosine of the smallest angle between them

d) Sine of the smallest angle between them

**Ans**: c

**Explanation**: The dot product of two vectors A and B is equal to the product of magnitude of A and B and cosine of the smallest angle between them. A.B = A B Cos θ where θ = smallest angle between A and B **Note**: The dot product of two vectors is a scalar quantity.

**3. What is the dimensional formula of work done?**

a) M1 L1 T-1 b) M1 L2 T-1

c) M1 L-1 T-2 d) M1 L2 T-2

**Ans**: d

**Explanation**: The dimensional formula of work done is M1 L2 T-2. Work is said to be done by a force when the body is displaced actually through some distance in the direction of applied force. The SI unit of Work is joule.

**4. What is the average power consumption of a heartbeat in an adult?**

a) 1.2 watt b) 112.5 watt c) 200 watt d) 500 watt

**Ans**: a

**Explanation**: Average power consumption by an adult in some of the common processes/activities: 1. Heartbeat – 1.2 watt 2. Sleeping – 75 watt 3. Slow walking – 200 watt 4. Bicycling – 500 watt

**5. Which of the following is true about the effect of altitude on the value of acceleration due to gravity?**

a) The acceleration due to gravity decreases with height

b) The acceleration due to gravity increases with height

c) The acceleration due to gravity is not dependent on height

d) None of the above

**Ans**: a

**Explanation**: The acceleration due to gravity decreases with height. G0= g(1-2h/R) where h is the height above the surface of the earth.

**6. If the time of revolution is T in a satellite, then kinetic energy is proportional to which of the following:**

a) T-4/3 b) T2/3 c) T-2/3 d) T-1/3

**Ans**: c

**Explanation**: The square of the period of any planet is proportional to the cube of the semi major axis of its orbit. So r is inversely proportional to cube root of the square of T. And Kinetic energy is inversely proportional to r. Therefore, K.E is directly proportional to (T)-2/3.

**7. The distance of Neptune and Saturn from sun is nearly 1013 and 1012 meters respectively. Assuming that they move in circular orbits, what will be the ratio of their periodic times?**

a) 40 b) 10√10 c) 20√20 d) 30√30

**Ans**: b

**Explanation**: By using Kepler‟s third law, Tneptune/Tsaturn = (Rneptune/Rsaturn) 3/2.

For more questions, visit the TS BC Study Circles Telegram group https://t.me/ Ukk7l_n7wJxmMjll.