Road to NDA : Daily Dose of Questions (Physics)

UPSC has already released the notification for NDA II 2021 which is scheduled to be conducted on 14th November 2021. Here we are publishing a large number of physics problems and questions. These physics questions are distributed among 7 sets of Questions for you which will be published in 7 days.

The first set (Set number 1) is being published on this post body itself and the rest of the sets (6 more) will be published in the coming days. The Standard of these sets is MEDIUM (not so hard). The questions provided in these sets are very important for the NDA exam. Attempt all these questions and let us know in the comment section. The winner of the quiz will be declared the next day. So here are 10 questions of physics:

1.Which one of the following cannot be the unit of frequency of a sound wave

A. dB
B. s^-1
C. Hz
D. min ^-1

2.If a stone is attached to a string and oscillate in a uniform vertical circular motion. Which of the following is not true?

A. The magnitude of the resultant force acting on the stone changes that depends upon the stone's position in the circle.
B. The tension in the string is minimum when the stone is at the highest point of the circular motion.
C. The kinetic energy is not constant for the stone.
D. The resultant acceleration is directed towards the centre of the circle.

3.The roller coaster car having just unclogged the top of the loop and moving down a frictionless track at the moment, which is shown below

Which direction is having the net force acting on the car?

A. A
B. B
C. C
D. D

4.A cube of side 10 cm and has a mass of 12 kg. What will be its relative density?

A. 16
B. 10
C. 12
D. 18

5.If a man's weight taken at the poles is 500 N. Will there be any change if he is measured at the equator?

A. Increases
B. Decreases
C. Increases then decreases
D. None of the above

6.If the period of an oscillation of a pendulum which measured as 3.0 second with a stopwatch with a least count of 1.5 sec, then what will be the percentage error in the measurement?

A. 50%
B. 30%
C. 25%
D. 15%

7.An electric dipole having two opposite charges of C, each separated by a distance of 4cm, which is settled in an electric field of N/C. What should be the torque acting on the dipole?

Nm
B.

Nm
C.

Nm
D.

8.Shweta can type 1500 words in half an hour. What is the typing speed of Shweta in words per minute?

A. 50
B. 60
C. 70
D. 80

9.The equivalent capacitance of the combination of three capacitors, each of capacitance A and B as shown in the given figure, is

B. 2C
C.

10.4. A sufficient long current-carrying conductor with 10 A current. Magnetic field intensity at a distance of 1cm from the conductor is

###ANSWERS###

1. Ans. A.

Frequency is the number of complete waves generated in one second. Mathematically, it is the reciprocal of the period. A period is a time taken by a wave to complete on revolution or to complete on complete cycle i.e. , where f is the frequency and T is the time period. therefore, from the formula, the unit of frequency can be , also it can be . Hertz or Hz is another unit of frequency.

Decibel or dB is the unit of measuring sound, more precisely the intensity of sound.

2. Ans. A.

Circular motion is a body movement in the circumference of a circle along with its circular path. It can be uniform motion, with constant speed and angular rate of rotation. In this form of motion, the magnitude of the tangential velocity and the body's radius remains constant. Therefore, since the centripetal force, which is the stone's resultant force, must remain the same.

3. Ans. C.

The car speeds up at that position, and therefore, it has a tangential component of the acceleration (pointing downward). At the same time, it is travelling in a circular path, so it has a radial component of the acceleration pointing towards the centre of the circle. So, the net force, which is the sum of these two components, can be best represented by C.

4. Ans. C.

Side of a cube= 10cm = 0.1m

Mass of cube, m= 12kg

Density= = = == 12000

Relative density= = = 12

5. Ans. B.

No, his weight will not be the same if he moves to the equator. There will be a decrease in his weight. As the radius of the earth increases from the poles towards the equator, then the value of g becomes greater at poles and start decreasing towards the equator. Also, the gravitational force decreases from poles to the equator.

6. Ans. A.

Given,

Time, T= 3 seconds

Least count, T= 1.5 seconds

The percentage error in time=

= =

= = 50%

7. Ans. B.

Given,

Charge, q= C

Electric field, E= N/C

Distance, d= 4 cm= m

Substitute the values in the formula of torque

T= qEd

T= Nm

8. Ans. A.

Total words= 1500

Time= 30 minutes

Speed= = = 50 words per minute

9. Ans. B.

The capacitor is connected across the circuit, which shows it is ineffective as the potential difference across the capacitoris zero, so there will be no current flow through it. Hence it is unable to perform. The remaining two capacitors are parallel to each other. So, the electric current will flow through these capacitors.

Resultant capacitance,=

= C+C= 2C

10. Ans. B.

Applying Ampere’s law as

Ampere’s law states that the line integral of the magnetic field across a closed loop is equal to the net current enclosed by the loop; the above is its mathematical expression.

Given current i=10 A

R(distance from conductor) = 1 cm = 10^-2m