16569 + Interview Questions in Physics

1.	A device called oscillator is used to send waves along a stretched string. The string is 20 cm long, and four complete waves fit along its length when the oscillator vibrates 30 time per second. For the waves on the string.(i) What is their wavelength?(ii) What is their frequency?(iii) What is their Speed?
Answer» A device called oscillator is used to send waves along a stretched string. The string is 20 cm long, and four complete waves fit along its length when the oscillator vibrates 30 time per second. For the waves on the string. (i) What is their wavelength? (ii) What is their frequency? (iii) What is their Speed?

Discussion

2.	What is the most basic requirement for producing electrical energy using a windmill?
Answer» What is the most basic requirement for producing electrical energy using a windmill?

Discussion

3.	Calculate the equivalent resistance in circuit diagram between the points A and B.
Answer» Calculate the equivalent resistance in circuit diagram between the points A and B.

3.

Calculate the equivalent resistance in circuit diagram between the points A and B.

Answer»

Calculate the equivalent resistance in circuit diagram between the points A and B.

Discussion

4.	A convex lens that has a very short focal length will cause a?
Answer» A convex lens that has a very short focal length will cause a?

Discussion

5.	(a) When does a fuse cut off current ? How does it do it ? (b) What is the maximum number of 60 W bulbs that can be run from the mains supply of 220 volts if you do not want to overload a 5 A fuse ?
Answer» (a) When does a fuse cut off current ? How does it do it ? (b) What is the maximum number of 60 W bulbs that can be run from the mains supply of 220 volts if you do not want to overload a 5 A fuse ?

5.

(a) When does a fuse cut off current ? How does it do it ? (b) What is the maximum number of 60 W bulbs that can be run from the mains supply of 220 volts if you do not want to overload a 5 A fuse ?

Answer»

(a) When does a fuse cut off current ? How does it do it ?

(b) What is the maximum number of 60 W bulbs that can be run from the mains supply of 220 volts if you do not want to overload a 5 A fuse ?

Discussion

6.	14.Suppose the sun expands so that its radius becomes 100 times its present radius and its surface temperature becomes half of its present value. The total energy emitted by it then will increase by a (a) 10 power 4 (b)625 (c) 256 (d) 16.
Answer» 14.Suppose the sun expands so that its radius becomes 100 times its present radius and its surface temperature becomes half of its present value. The total energy emitted by it then will increase by a (a) 10 power 4 (b)625 (c) 256 (d) 16.

Discussion

7.	To find the focal length of a concave mirror Rahul focuses a distant object with his mirror. The chosen object should be
Answer» To find the focal length of a concave mirror Rahul focuses a distant object with his mirror. The chosen object should be

Discussion

8.	A solenoid wound over a rectangular frame. If all the linear dimensions of the frame are increased by a factor of 3 and the number of turns per unit length remains the same, the self inductance increased by a factor of ?
Answer» A solenoid wound over a rectangular frame. If all the linear dimensions of the frame are increased by a factor of 3 and the number of turns per unit length remains the same, the self inductance increased by a factor of ?

Discussion

9.	In a graph is R the same even if we interchange V in the X axis and I in the Y axis
Answer» In a graph is R the same even if we interchange V in the X axis and I in the Y axis

Discussion

10.	Look at the figure given below and answer question based on that. Iron filings are sprinkled on a cardboard perpendicular to which a current carrying copper wire runs. A compass is placed at point 'P'. The other components of the circuit have their usual meaningsIf the polarity of the battery in the circuit is changed then__
Answer» Look at the figure given below and answer question based on that. Iron filings are sprinkled on a cardboard perpendicular to which a current carrying copper wire runs. A compass is placed at point 'P'. The other components of the circuit have their usual meanings If the polarity of the battery in the circuit is changed then__

10.

Look at the figure given below and answer question based on that. Iron filings are sprinkled on a cardboard perpendicular to which a current carrying copper wire runs. A compass is placed at point 'P'. The other components of the circuit have their usual meaningsIf the polarity of the battery in the circuit is changed then__

Answer»

Look at the figure given below and answer question based on that.

Iron filings are sprinkled on a cardboard perpendicular to which a current carrying copper wire runs. A compass is placed at point 'P'. The other components of the circuit have their usual meanings

If the polarity of the battery in the circuit is changed then__

Discussion

11.	Is the position of a star as seen by us its true position? Justify your answer.
Answer» Is the position of a star as seen by us its true position? Justify your answer.

Discussion

12.	Explain in brief the reason for each of the following: (a) Advanced Sun-rise (b) Delayed Sun-Set (c) Twinkling of stars
Answer» Explain in brief the reason for each of the following: (a) Advanced Sun-rise (b) Delayed Sun-Set (c) Twinkling of stars

Discussion

13.	In a Young's double slit experiment, the separation between the two slits is 2π mm. The distance of the screen from the slits is 50 cm. If the wavelength of light used is 4000 A∘, then the angular position of first dark fringe is
Answer» In a Young's double slit experiment, the separation between the two slits is $\frac{2}{π} m m$ . The distance of the screen from the slits is $50 c m$ . If the wavelength of light used is $4000 A^{\circ}$ , then the angular position of first dark fringe is

Discussion

14.	The magnetic field lines produced by a bar magnet : (a) originate from the south pole and end at its north pole (b) originate from the north pole and end at its each pole (c) originate from the north pole and end at its south pole (d) originate from the south pole and end at its west pole
Answer» The magnetic field lines produced by a bar magnet : (a) originate from the south pole and end at its north pole (b) originate from the north pole and end at its each pole (c) originate from the north pole and end at its south pole (d) originate from the south pole and end at its west pole

14.

The magnetic field lines produced by a bar magnet : (a) originate from the south pole and end at its north pole (b) originate from the north pole and end at its each pole (c) originate from the north pole and end at its south pole (d) originate from the south pole and end at its west pole

Answer»

The magnetic field lines produced by a bar magnet :

(a) originate from the south pole and end at its north pole

(b) originate from the north pole and end at its each pole

(c) originate from the north pole and end at its south pole

(d) originate from the south pole and end at its west pole

Discussion

15.	The current flowing through a device is 4 mA at 30 V and 6 mA at 60 V .The dynamic resis†an ce is
Answer» The current flowing through a device is 4 mA at 30 V and 6 mA at 60 V .The dynamic resis†an ce is

Discussion

16.	Which electrical current alters its direction in regular intervals of time?
Answer» Which electrical current alters its direction in regular intervals of time?

Discussion

17.	A body A starts from rest with an acceleration a1 . After 2 seconds, another body B starts from rest with an acceleration a2 . If they travel equal distances in the 5th second after the start of A, then the ratio a1:a2 is equal to
Answer» A body $A$ starts from rest with an acceleration $a_{1}$ . After $2$ seconds, another body $B$ starts from rest with an acceleration $a_{2}$ . If they travel equal distances in the $5^{th} second$ after the start of $A$ , then the ratio $a_{1} : a_{2}$ is equal to

Discussion

18.	Water falls from a height of 500m. What is the rise in temperature of water at bottom if whole energy remains in the water?
Answer» Water falls from a height of 500m. What is the rise in temperature of water at bottom if whole energy remains in the water?

Discussion

19.	In a step up transformer, the ratio of turns of primary to secondary is 5:6 and the primary voltage is 410 V. If the current in the primary is 4 A, then what is the load current?
Answer» In a step up transformer, the ratio of turns of primary to secondary is $5 : 6$ and the primary voltage is $410 V$ . If the current in the primary is $4 A$ , then what is the load current?

Discussion

20.	A equi-convex lens is made of glass of refractive index 1.5 and has a focal length 10 cm in air. The lens is cut into two equal halves along a plane perpendicular to its principal axis to yield two plano-convex lenses. If one of the plano-convex lens is immersed in water the new focal length of it is (μw=43)
Answer» A equi-convex lens is made of glass of refractive index $1.5$ and has a focal length $10 cm$ in air. The lens is cut into two equal halves along a plane perpendicular to its principal axis to yield two plano-convex lenses. If one of the plano-convex lens is immersed in water the new focal length of it is $(μ_{w} = \frac{4}{3})$

Discussion

21.	In the electric circuit shown in figure, the reading of voltmeter V1 is 26 volt, and the reading of ammeter A1 is 2 ampere. The value of resistance x is - (all instruments are ideal)
Answer» In the electric circuit shown in figure, the reading of voltmeter $V_{1}$ is 26 volt, and the reading of ammeter $A_{1}$ is 2 ampere. The value of resistance $x$ is - (all instruments are ideal)

Discussion

22.	A body is having a charge of 10 C. When it comes in contact with an uncharged body, it looses 1.6 C of charge. Find the number of electrons lost.
Answer» A body is having a charge of 10 C. When it comes in contact with an uncharged body, it looses 1.6 C of charge. Find the number of electrons lost.

Discussion

23.	A carnot engine whose sink is at 300 Kelvin as an efficiency of 40% by how much should the temperature of source be increased to as to increase its efficiency by 50% of original efficiency. 250 degree Celsius 250 Kelvin
Answer» A carnot engine whose sink is at 300 Kelvin as an efficiency of 40% by how much should the temperature of source be increased to as to increase its efficiency by 50% of original efficiency. 250 degree Celsius 250 Kelvin

Discussion

24.	Power generated across uniform wire connected across a supply is H. If the wire is cut into n equal parts and all the parts are connected in parallel across the same supply, the total power generated in the wire is
Answer» Power generated across uniform wire connected across a supply is $H$ . If the wire is cut into $n$ equal parts and all the parts are connected in parallel across the same supply, the total power generated in the wire is

Discussion

25.	93.Three rods of materials X and three rods of material Y are connected as shown. All are identical in length and cross sectional area. If end A is maintained at 60C, end E at 10C, thermal conductivity of X is 0.92 cal/sec-C and that of Y is 0.46 cal/sec-C then find the temperature of junctions B,C,D A 20C, 30C, 20C B 30C, 20C, 20C C 20C, 20C, 30C D 20C, 20C, 20C
Answer» 93.Three rods of materials X and three rods of material Y are connected as shown. All are identical in length and cross sectional area. If end A is maintained at 60C, end E at 10C, thermal conductivity of X is 0.92 cal/sec-C and that of Y is 0.46 cal/sec-C then find the temperature of junctions B,C,D A 20C, 30C, 20C B 30C, 20C, 20C C 20C, 20C, 30C D 20C, 20C, 20C

Discussion

26.	A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil?(ii) withdrawn from inside the coil?(iii) held stationary inside the coil?
Answer» A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil? (ii) withdrawn from inside the coil? (iii) held stationary inside the coil?

Discussion

27.	The focal length of a convex lens is 25 cm. Express its power with sign.
Answer» The focal length of a convex lens is 25 cm. Express its power with sign.

Discussion

28.	If the distance between the sun and the earth is increased to three times then the attraction between the two will change by how much percentage?
Answer» If the distance between the sun and the earth is increased to three times then the attraction between the two will change by how much percentage?

Discussion

29.	A particle of mass m moves with constant speed v on a circular path of radius r. Find magnitudeof average force on it in half revolution.
Answer» A particle of mass m moves with constant speed v on a circular path of radius r. Find magnitudeof average force on it in half revolution.

Discussion

30.	Question 5A light ray enters from medium A to medium B as shown in figure. The refractive index of medium B relative to A will be:(a) greater than unity(b) less than unity(c) equal to unity(d) zero
Answer» Question 5 A light ray enters from medium A to medium B as shown in figure. The refractive index of medium B relative to A will be: (a) greater than unity (b) less than unity (c) equal to unity (d) zero

Discussion

31.	Complete the following sentences : (a) The pitch of sound increases if its frequency ...................................... (b) If the amplitude of a sound is halved, its loudness becomes ......................
Answer» Complete the following sentences : (a) The pitch of sound increases if its frequency ...................................... (b) If the amplitude of a sound is halved, its loudness becomes ......................

31.

Complete the following sentences : (a) The pitch of sound increases if its frequency ...................................... (b) If the amplitude of a sound is halved, its loudness becomes ......................

Answer»

Complete the following sentences :

(a) The pitch of sound increases if its frequency ......................................

(b) If the amplitude of a sound is halved, its loudness becomes ......................

Discussion

32.	Give two examples each for a solid, liquid, and gaseous fuel along with some important uses.
Answer» Give two examples each for a solid, liquid, and gaseous fuel along with some important uses.

Discussion

33.	A wire of resistance 5ohm is bent in the form of a closed circle. Find the resistance between two points at the ends of any diameter of the circle.
Answer» A wire of resistance 5ohm is bent in the form of a closed circle. Find the resistance between two points at the ends of any diameter of the circle.

Discussion

34.	Find the angle between the emergent ray and incident ray when the light goes from air to glass slab. Given μglass=1.5
Answer» Find the angle between the emergent ray and incident ray when the light goes from air to glass slab. Given $μ_{g l a s s} = 1.5$

34.

Find the angle between the emergent ray and incident ray when the light goes from air to glass slab. Given μglass=1.5

Answer»

Find the angle between the emergent ray and incident ray when the light goes from air to glass slab.
Given $μ_{g l a s s} = 1.5$

Discussion

35.	Two wires of same metal have the same length, but their cross-sections are in the ratio 3:1. They are joined in series. If the resistance of the thicker wire is 10 Ω, then total resistance of the combination will be
Answer» Two wires of same metal have the same length, but their cross-sections are in the ratio $3 : 1$ . They are joined in series. If the resistance of the thicker wire is $10 Ω$ , then total resistance of the combination will be

Discussion

36.

Three containers C1,C2 and C3 have water at different temperatures. The table below shows the final temperature T when different amount of water (given in litres) are taken from each container and mixed (assume no loss of heat during the process) C1 C2 C3 T 1 L 2 L - 60∘C - 1 L 2 L 30∘C 2 L - 1 L 60∘C 1 L 1 L 1 L θ The value of θ (in °C to the nearest integer) is

Answer» Three containers

C_{1}, C_{2}

and

C_{3}

have water at different temperatures. The table below shows the final temperature

T

when different amount of water (given in litres) are taken from each container and mixed (assume no loss of heat during the process)

$C_{1}$	$C_{2}$	$C_{3}$	$T$
$1 L$	$2 L$	-	$60^{\circ} C$
-	$1 L$	$2 L$	$30^{\circ} C$
$2 L$	-	$1 L$	$60^{\circ} C$
$1 L$	$1 L$	$1 L$	$θ$

The value of

θ

(in °C to the nearest integer) is

Discussion

37.	What is lens formula and derivation
Answer» What is lens formula and derivation

Discussion

38.	The charge of an electron is known to be 1.6×10−19 C. In a circuit, the current flowing is 1 A. How many electrons will be flowing through the circuit per second?
Answer» The charge of an electron is known to be $1.6 \times 10^{- 19} C$ . In a circuit, the current flowing is $1 A$ . How many electrons will be flowing through the circuit per second?

Discussion

39.	what-are-strong-nuclear-forces-applied-by-nucleus-on-protons?what-are-its-effects?how-these-nuclear-forces-are-formed-in-the-nucleus?
Answer» what-are-strong-nuclear-forces-applied-by-nucleus-on-protons?what-are-its-effects?how-these-nuclear-forces-are-formed-in-the-nucleus?

Discussion

40.	Two planets of radii r1 and r2 are made from the same material. The ratio of the acceleration due to gravity g1g2 at the surface of the two planets is:
Answer» Two planets of radii $r_{1}$ and $r_{2}$ are made from the same material. The ratio of the acceleration due to gravity $\frac{g_{1}}{g_{2}}$ at the surface of the two planets is:

Discussion

41.	Name one effect produced by the scattering of light by the atmosphere.
Answer» Name one effect produced by the scattering of light by the atmosphere.

Discussion

42.	A copper wire having resis†an ce 0.01 ohm in each metre is used to wind a400 turn solenoid of radius 1 cm and length 20 cm. Find the emf of a battery when connected across the solenoid will cause a magnetic field of 10^- Tesla near the centre of the solenoid.
Answer» A copper wire having resis†an ce 0.01 ohm in each metre is used to wind a400 turn solenoid of radius 1 cm and length 20 cm. Find the emf of a battery when connected across the solenoid will cause a magnetic field of 10^- Tesla near the centre of the solenoid.

Discussion

43.	Why does only refraction occur on the second surface of the same prism, and not dispersion or recombination?
Answer» Why does only refraction occur on the second surface of the same prism, and not dispersion or recombination?

Discussion

44.	A current carrying conductor placed in magnetic field experiences a force. The amount of force experienced by a current carrying conductor in magnetic field can be increased by:
Answer» A current carrying conductor placed in magnetic field experiences a force. The amount of force experienced by a current carrying conductor in magnetic field can be increased by:

Discussion

45.	Why is the angle of incidence equal to the angle of reflection? What is the reason behind it? Is it just a law that we have to memorize??.
Answer» Why is the angle of incidence equal to the angle of reflection? What is the reason behind it? Is it just a law that we have to memorize??.

Discussion

46.	Two lenses in contact made of materials with dispersive power in the ratio 2:1 behaves as an achromatic lens of focal length 10 cm. The individual focal length of the lenses are:
Answer» Two lenses in contact made of materials with dispersive power in the ratio $2 : 1$ behaves as an achromatic lens of focal length $10 cm$ . The individual focal length of the lenses are:

Discussion

47.	When Tyndall effect is observed? Explain.
Answer» When Tyndall effect is observed? Explain.

Discussion

48.	The radius of curvature of a convex mirror is 40 cm. Find its focal length.
Answer» The radius of curvature of a convex mirror is 40 cm. Find its focal length.

Discussion

49.	Magnetic field at point O due to the structure is
Answer» Magnetic field at point O due to the structure is

Discussion

50.	Why household wiring is done in parallel wiring system?
Answer» Why household wiring is done in parallel wiring system?

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

What is the most basic requirement for producing electrical energy using a windmill?

Calculate the equivalent resistance in circuit diagram between the points A and B.

A convex lens that has a very short focal length will cause a?

(a) When does a fuse cut off current ? How does it do it ? (b) What is the maximum number of 60 W bulbs that can be run from the mains supply of 220 volts if you do not want to overload a 5 A fuse ?

14.Suppose the sun expands so that its radius becomes 100 times its present radius and its surface temperature becomes half of its present value. The total energy emitted by it then will increase by a (a) 10 power 4 (b)625 (c) 256 (d) 16.

To find the focal length of a concave mirror Rahul focuses a distant object with his mirror. The chosen object should be

A solenoid wound over a rectangular frame. If all the linear dimensions of the frame are increased by a factor of 3 and the number of turns per unit length remains the same, the self inductance increased by a factor of ?

In a graph is R the same even if we interchange V in the X axis and I in the Y axis

Is the position of a star as seen by us its true position? Justify your answer.

Explain in brief the reason for each of the following: (a) Advanced Sun-rise (b) Delayed Sun-Set (c) Twinkling of stars

In a Young's double slit experiment, the separation between the two slits is 2π mm. The distance of the screen from the slits is 50 cm. If the wavelength of light used is 4000 A∘, then the angular position of first dark fringe is

The magnetic field lines produced by a bar magnet : (a) originate from the south pole and end at its north pole (b) originate from the north pole and end at its each pole (c) originate from the north pole and end at its south pole (d) originate from the south pole and end at its west pole

The current flowing through a device is 4 mA at 30 V and 6 mA at 60 V .The dynamic resis†an ce is

Which electrical current alters its direction in regular intervals of time?

A body A starts from rest with an acceleration a1 . After 2 seconds, another body B starts from rest with an acceleration a2 . If they travel equal distances in the 5th second after the start of A, then the ratio a1:a2 is equal to

Water falls from a height of 500m. What is the rise in temperature of water at bottom if whole energy remains in the water?

In a step up transformer, the ratio of turns of primary to secondary is 5:6 and the primary voltage is 410 V. If the current in the primary is 4 A, then what is the load current?

In the electric circuit shown in figure, the reading of voltmeter V1 is 26 volt, and the reading of ammeter A1 is 2 ampere. The value of resistance x is - (all instruments are ideal)

A body is having a charge of 10 C. When it comes in contact with an uncharged body, it looses 1.6 C of charge. Find the number of electrons lost.

A carnot engine whose sink is at 300 Kelvin as an efficiency of 40% by how much should the temperature of source be increased to as to increase its efficiency by 50% of original efficiency. 250 degree Celsius 250 Kelvin

Power generated across uniform wire connected across a supply is H. If the wire is cut into n equal parts and all the parts are connected in parallel across the same supply, the total power generated in the wire is

A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil?(ii) withdrawn from inside the coil?(iii) held stationary inside the coil?

The focal length of a convex lens is 25 cm. Express its power with sign.

If the distance between the sun and the earth is increased to three times then the attraction between the two will change by how much percentage?

A particle of mass m moves with constant speed v on a circular path of radius r. Find magnitudeof average force on it in half revolution.

Question 5A light ray enters from medium A to medium B as shown in figure. The refractive index of medium B relative to A will be:(a) greater than unity(b) less than unity(c) equal to unity(d) zero

Complete the following sentences : (a) The pitch of sound increases if its frequency ...................................... (b) If the amplitude of a sound is halved, its loudness becomes ......................

Give two examples each for a solid, liquid, and gaseous fuel along with some important uses.

A wire of resistance 5ohm is bent in the form of a closed circle. Find the resistance between two points at the ends of any diameter of the circle.

Find the angle between the emergent ray and incident ray when the light goes from air to glass slab. Given μglass=1.5

Two wires of same metal have the same length, but their cross-sections are in the ratio 3:1. They are joined in series. If the resistance of the thicker wire is 10 Ω, then total resistance of the combination will be

What is lens formula and derivation

The charge of an electron is known to be 1.6×10−19 C. In a circuit, the current flowing is 1 A. How many electrons will be flowing through the circuit per second?

what-are-strong-nuclear-forces-applied-by-nucleus-on-protons?what-are-its-effects?how-these-nuclear-forces-are-formed-in-the-nucleus?

Two planets of radii r1 and r2 ​are made from the same material. The ratio of the acceleration due to gravity g1g2​ at the surface of the two planets is:

Name one effect produced by the scattering of light by the atmosphere.

A copper wire having resis†an ce 0.01 ohm in each metre is used to wind a400 turn solenoid of radius 1 cm and length 20 cm. Find the emf of a battery when connected across the solenoid will cause a magnetic field of 10^- Tesla near the centre of the solenoid.

Why does only refraction occur on the second surface of the same prism, and not dispersion or recombination?

A current carrying conductor placed in magnetic field experiences a force. The amount of force experienced by a current carrying conductor in magnetic field can be increased by:

Why is the angle of incidence equal to the angle of reflection? What is the reason behind it? Is it just a law that we have to memorize??.

Two lenses in contact made of materials with dispersive power in the ratio 2:1 behaves as an achromatic lens of focal length 10 cm. The individual focal length of the lenses are:

When Tyndall effect is observed? Explain.

The radius of curvature of a convex mirror is 40 cm. Find its focal length.

Magnetic field at point O due to the structure is

Why household wiring is done in parallel wiring system?

Two planets of radii r1 and r2 are made from the same material. The ratio of the acceleration due to gravity g1g2 at the surface of the two planets is: