16569 + Interview Questions in Physics

1.	Why do stars appear to twinkle?
Answer» Why do stars appear to twinkle?

Discussion

2.	What is the major difference between the simple alternator and most practical alternators ?
Answer» What is the major difference between the simple alternator and most practical alternators ?

Discussion

3.

Following observations were taken with a transit theodolite fitted with stadia wires. The line of sight was horizontal and the staff was held vertical. Stadia hair Reading on staff (m) Top hair 1.646 Middle hair 2.348 Bottom hair 2.780 Other data 0.0 The tacheometer constants K and C are 100 and 0.6 m respectively. The horizontal distance between staff and instrument is _______ m.114

Answer» Following observations were taken with a transit theodolite fitted with stadia wires. The line of sight was horizontal and the staff was held vertical.

Stadia hair	Reading on staff (m)
Top hair	1.646
Middle hair	2.348
Bottom hair	2.780
Other data	0.0

The tacheometer constants K and C are 100 and 0.6 m respectively. The horizontal distance between staff and instrument is _______ m.

114

Discussion

4.	47. Vapour pressure of pure water if lowering of vapour pressure becomes 0.125 torr when 50g of cane sugar is added to 0.5 litre of water is approximately ??
Answer» 47. Vapour pressure of pure water if lowering of vapour pressure becomes 0.125 torr when 50g of cane sugar is added to 0.5 litre of water is approximately ??

Discussion

5.	An insect is sitting in front of a plane mirror at a distance 1 m from it. (a) Where is the image of the insect formed ? (b) What is the distance between the insect and its image ?
Answer» An insect is sitting in front of a plane mirror at a distance 1 m from it. (a) Where is the image of the insect formed ? (b) What is the distance between the insect and its image ?

5.

An insect is sitting in front of a plane mirror at a distance 1 m from it. (a) Where is the image of the insect formed ? (b) What is the distance between the insect and its image ?

Answer»

An insect is sitting in front of a plane mirror at a distance 1 m from it.

(a) Where is the image of the insect formed ?

(b) What is the distance between the insect and its image ?

Discussion

6.	why are angular nodes called angular nodes? like radial nodes , okay they are spherical and have a radius, but angular nodes are also c/a nodal planes, and I don't get what nodal planes has to do with angles?
Answer» why are angular nodes called angular nodes? like radial nodes , okay they are spherical and have a radius, but angular nodes are also c/a nodal planes, and I don't get what nodal planes has to do with angles?

Discussion

7.	Why wavelength depend upon colour?
Answer» Why wavelength depend upon colour?

Discussion

8.	Two cars move towards each other with same speed. Speed of sound is 340 m/s. If the frequency of tone of horn sounded by one car becomes 107 times of original when heard by other, then the speed of each car is
Answer» Two cars move towards each other with same speed. Speed of sound is $340 m / s$ . If the frequency of tone of horn sounded by one car becomes $\frac{10}{7}$ times of original when heard by other, then the speed of each car is

Discussion

9.	Question 12Why does the Sun appear reddish early in the morning?
Answer» Question 12 Why does the Sun appear reddish early in the morning?

Discussion

10.	The values of two resistors are R, = (6 \pm 0.3) k2and R2 (10 0.2) k2. The percentage error inthe equivalent resistance when they are connectedin parallel is(1) 5.125%(2) 2%(3) 3.875%(4) 7%
Answer» The values of two resistors are R, = (6 \pm 0.3) k2and R2 (10 0.2) k2. The percentage error inthe equivalent resistance when they are connectedin parallel is(1) 5.125%(2) 2%(3) 3.875%(4) 7%

Discussion

11.	Name a liquid whose mass density is less than that of water but is optically denser than water.
Answer» Name a liquid whose mass density is less than that of water but is optically denser than water.

Discussion

12.	Why we take notation of SHE as H2/H+ Why not H+/H2 as it can act as both cathode and anode
Answer» Why we take notation of SHE as H2/H+ Why not H+/H2 as it can act as both cathode and anode

Discussion

13.	what is diffraction and intereference of light?
Answer» what is diffraction and intereference of light?

Discussion

14.	A magnet oscillating in a horizontal plane has a time period of 2 sec at a place where the angle of dip is 30∘ and 3 sec at another place where the angle of dip is 60∘. The ratio of resultant magnetic fields at the two places is:
Answer» A magnet oscillating in a horizontal plane has a time period of $2 sec$ at a place where the angle of dip is $30^{\circ}$ and $3 sec$ at another place where the angle of dip is $60^{\circ}$ . The ratio of resultant magnetic fields at the two places is:

Discussion

15.	Are the ray PM and PT opposite rays? Give reasons for your answer.
Answer» Are the ray PM and PT opposite rays? Give reasons for your answer.

Discussion

16.	Why is the mass of a body concentrated at the center of gravity?
Answer» Why is the mass of a body concentrated at the center of gravity?

Discussion

17.	a rod of length l and cross sectional area a lies along the x - axis between x = l and x = 2l. resistivity of rod varies according to law p = pnot(x/l). if the rod is subjected to potential difference v0, then current in the rod is
Answer» a rod of length l and cross sectional area a lies along the x - axis between x = l and x = 2l. resistivity of rod varies according to law p = pnot(x/l). if the rod is subjected to potential difference v0, then current in the rod is

Discussion

18.	Rays parallel to the principal axis of a concave or convex mirror meet or appear to come from which point?
Answer» Rays parallel to the principal axis of a concave or convex mirror meet or appear to come from which point?

Discussion

19.	charge of 10micro coulomb is placed at the origin of x-y coordinate system. The potential difference between two points (0, a) and (a, 0) in volt will be
Answer» charge of 10micro coulomb is placed at the origin of x-y coordinate system. The potential difference between two points (0, a) and (a, 0) in volt will be

Discussion

20.	The frequency of a car horn encountered a change from 400 Hz to 500 Hz, when the car approaches a vertical wall. If the speed of sound is 330 m/s. Then the speed of car is _____ km/h.
Answer» The frequency of a car horn encountered a change from $400 Hz$ to $500 Hz$ , when the car approaches a vertical wall. If the speed of sound is $330 m/s$ . Then the speed of car is _____ $km/h$ .

Discussion

21.	The bulb in the circuit shown below does not glow. Which of the following labelled parts is responsible for this?
Answer» The bulb in the circuit shown below does not glow. Which of the following labelled parts is responsible for this?

Discussion

22.	94. If the escape velocity at earth is 11.2km/s , then what will be the escape velocity of planet having mass 4 times of earth and gravitational acceleration equal to earth??
Answer» 94. If the escape velocity at earth is 11.2km/s , then what will be the escape velocity of planet having mass 4 times of earth and gravitational acceleration equal to earth??

Discussion

23.	For the myopic eye, the defect is cured by using:
Answer» For the myopic eye, the defect is cured by using:

Discussion

24.	A dip circle is taken to a magnetic pole. Initially itwas in vertical direction. If dip circle is now turnedby 90 in a vertical plane, the needle will(1) Stay in horizontal direction(2) Stay in vertical direction(3) Can stay in any direction it is released(4) Can stay in any direction except vertical orhorizontal
Answer» A dip circle is taken to a magnetic pole. Initially it was in vertical direction. If dip circle is now turned by 90 in a vertical plane, the needle will (1) Stay in horizontal direction (2) Stay in vertical direction (3) Can stay in any direction it is released (4) Can stay in any direction except vertical or horizontal

Discussion

25.	Two thin identical shape plano-convex lenses L1(μ1=1.4) and L2(μ2=1.5) with radius of curvature R=20 cm have been arranged as shown in figure.A parallel beam of light is incident on the system of the lenses, the position of image formed with respect to the common optical center is:
Answer» Two thin identical shape plano-convex lenses $L_{1} (μ_{1} = 1.4)$ and $L_{2} (μ_{2} = 1.5)$ with radius of curvature $R = 20 cm$ have been arranged as shown in figure. A parallel beam of light is incident on the system of the lenses, the position of image formed with respect to the common optical center is:

Discussion

26.	Two similar circular loops of radius R are lying concentrically with their planes at right angles to each other. The current flowing in them are 'i' and 'i root 3' respectively. The magnetic field at the centre of the coil is?
Answer» Two similar circular loops of radius R are lying concentrically with their planes at right angles to each other. The current flowing in them are 'i' and 'i root 3' respectively. The magnetic field at the centre of the coil is?

Discussion

27.	How much momentum will a dumbbell of mass 10 kg transfer to the floor if it falls from a height of 80 cm (assume that the dumbbell stops after hitting the ground)? Take g = 10 ms-2 .
Answer» How much momentum will a dumbbell of mass 10 kg transfer to the floor if it falls from a height of 80 cm (assume that the dumbbell stops after hitting the ground)? Take g = 10 ms^-2.

Discussion

28.	(a) What is myopia?(b) What are the causes of myopia?(c) Draw three labelled ray-diagrams to show the defect of vision called myopia and how it is corrected by the use of lenses.(d) The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the defect?
Answer» (a) What is myopia? (b) What are the causes of myopia? (c) Draw three labelled ray-diagrams to show the defect of vision called myopia and how it is corrected by the use of lenses. (d) The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the defect?

Discussion

29.	Can you tell out of the following machines in which electromagnet is used?
Answer» Can you tell out of the following machines in which electromagnet is used?

Discussion

30.	standrad deviation short cut method formula proof
Answer» standrad deviation short cut method formula proof

Discussion

31.	A solenoid has a core of a material with relative permeability 500. The winding of the solenoid are insulated from the core and carry current of 5 A. If the number of turns are 1000 per metre, what is the intensity of magnetization of the core?
Answer» A solenoid has a core of a material with relative permeability $500$ . The winding of the solenoid are insulated from the core and carry current of $5 A$ . If the number of turns are $1000$ per metre, what is the intensity of magnetization of the core?

Discussion

32.	If 3 bodies A, B and C are connected to each other, the temperature of body A is 23°C, B is at 119°C and C is at 78 °C, then from which body/bodies will the heat flow from?
Answer» If 3 bodies A, B and C are connected to each other, the temperature of body A is 23°C, B is at 119°C and C is at 78 °C, then from which body/bodies will the heat flow from?

Discussion

33.	U−235 requires a neutron to be bombarded into it to undergo fission because
Answer» $U - 235$ requires a neutron to be bombarded into it to undergo fission because

Discussion

34.	Silver is the best conductor of electricity can you say why electric wires are not made up of silver?
Answer» Silver is the best conductor of electricity can you say why electric wires are not made up of silver?

Discussion

35.	The harnessing of which of the following leads to the destruction of large eco-systems ? (a) thermal power (b) tidal power (c) hydro power (d) geothermal power
Answer» The harnessing of which of the following leads to the destruction of large eco-systems ? (a) thermal power (b) tidal power (c) hydro power (d) geothermal power

Discussion

36.	An object of the height of 2 cm is placed perpendicular to the principal axis of a concave lens of the focal length of 12 cm. find the height of the image, if the object is placed at a distance of 8 cm from the lens?
Answer» An object of the height of 2 cm is placed perpendicular to the principal axis of a concave lens of the focal length of 12 cm. find the height of the image, if the object is placed at a distance of 8 cm from the lens?

Discussion

37.	Which of the following represents the current-time graph of a generator with slip rings?
Answer» Which of the following represents the current-time graph of a generator with slip rings?

Discussion

38.	a barometer is constructed with its tube having radius 1.0mm.assume that the surface of mercury in the tube is spherical in shape.if the atmospheric pressure is equal to 76cm of mercury,what will be the height raised in the barometer tube?the contact angle of mercury with glass =135degree and surface tension of mercury=0.465N/m.density of mercury=13600kg/m^3.
Answer» a barometer is constructed with its tube having radius 1.0mm.assume that the surface of mercury in the tube is spherical in shape.if the atmospheric pressure is equal to 76cm of mercury,what will be the height raised in the barometer tube?the contact angle of mercury with glass =135degree and surface tension of mercury=0.465N/m.density of mercury=13600kg/m^3.

Discussion

39.	List various fields where cryogenics can be used. Also, explain in brief how it finds its application.
Answer» List various fields where cryogenics can be used. Also, explain in brief how it finds its application.

Discussion

40.	The commercial unit of energy is : (a) watt (b) watt-hour (c) kilowatt-hour (d) kilo-joule
Answer» The commercial unit of energy is : (a) watt (b) watt-hour (c) kilowatt-hour (d) kilo-joule

40.

The commercial unit of energy is : (a) watt (b) watt-hour (c) kilowatt-hour (d) kilo-joule

Answer»

The commercial unit of energy is :

(a) watt

(b) watt-hour

(c) kilowatt-hour

(d) kilo-joule

Discussion

41.	All formulas of chapter light reflection and refraction
Answer» All formulas of chapter light reflection and refraction

Discussion

42.	The atomic numbers and mass numbers of X respectively ? 21884PO→X+42He
Answer» The atomic numbers and mass numbers of X respectively ? $_{84}^{218} P O \to X +_{2}^{4} H e$

Discussion

43.	If the power of a lens is + 0.1 D and if the object of size 2 cm is placed 5 cm before the lens. Find the size and position of the image formed.
Answer» If the power of a lens is + 0.1 D and if the object of size 2 cm is placed 5 cm before the lens. Find the size and position of the image formed.

Discussion

44.	While calculating heat energy, what should be the unit of time? Second or hours?
Answer» While calculating heat energy, what should be the unit of time? Second or hours?

Discussion

45.	The Figure shows a spherical concave mirror with its pole at (0,0) and principal axis along the x-axis. There is a point object located at (−40 cm,1 cm). Find the position of the image.
Answer» The Figure shows a spherical concave mirror with its pole at $(0, 0)$ and principal axis along the $x$ -axis. There is a point object located at $(- 40 cm, 1 cm)$ . Find the position of the image.

Discussion

46.	A material of resistivity ρ is formed in the shape of a truncated cone of altitude h. The top end has a radius "a" while bottom end has a radius "b". Assuming a uniform current density through any circular cross-section of the cone, find the resistance between the two ends.
Answer» A material of resistivity $ρ$ is formed in the shape of a truncated cone of altitude h. The top end has a radius "a" while bottom end has a radius "b". Assuming a uniform current density through any circular cross-section of the cone, find the resistance between the two ends.

Discussion

47.	A ray of light travelling in the air falls on the surface of a plastic slab at an angle 53° ( sin530 = 45) with the normal. The refractive index of plastic slab is 1.6. Calculate the angle of refraction.
Answer» A ray of light travelling in the air falls on the surface of a plastic slab at an angle 53° ( $s i n 53^{0}$ = $\frac{4}{5}$ ) with the normal. The refractive index of plastic slab is 1.6. Calculate the angle of refraction.

Discussion

48.	In a block and tackle system consisting of 3 pulleys, a load of 75 kgf is raised with an effort of 25 kgf. Find : (i) the mechanical advantage, (ii) the velocity ratio, and (iii) the efficiency.
Answer» In a block and tackle system consisting of 3 pulleys, a load of 75 kgf is raised with an effort of 25 kgf. Find : (i) the mechanical advantage, (ii) the velocity ratio, and (iii) the efficiency.

Discussion

49.	Q. At the place horizontal and vertical components of Earth's magnetic field are as follows BH = 1 G 10^° west of north Bv=1 G vertically downward then the dip angle and declination are respectively??
Answer» Q. At the place horizontal and vertical components of Earth's magnetic field are as follows BH = 1 G 10^° west of north Bv=1 G vertically downward then the dip angle and declination are respectively??

Discussion

50.	71.A long straight wires carries a current I let B1 be the magnetic field at the point p at a distance d from the wire consider a section of length l of this wire such that the point p lies on a perpendicular bisector of the section . Let BE be the magnetic field at this point due to this section only find the value d/l so that B2 differ from B1 by 1%
Answer» 71.A long straight wires carries a current I let B1 be the magnetic field at the point p at a distance d from the wire consider a section of length l of this wire such that the point p lies on a perpendicular bisector of the section . Let BE be the magnetic field at this point due to this section only find the value d/l so that B2 differ from B1 by 1%

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Why do stars appear to twinkle?

What is the major difference between the simple alternator and most practical alternators ?

47. Vapour pressure of pure water if lowering of vapour pressure becomes 0.125 torr when 50g of cane sugar is added to 0.5 litre of water is approximately ??

An insect is sitting in front of a plane mirror at a distance 1 m from it. (a) Where is the image of the insect formed ? (b) What is the distance between the insect and its image ?

why are angular nodes called angular nodes? like radial nodes , okay they are spherical and have a radius, but angular nodes are also c/a nodal planes, and I don't get what nodal planes has to do with angles?

Why wavelength depend upon colour?

Two cars move towards each other with same speed. Speed of sound is 340 m/s. If the frequency of tone of horn sounded by one car becomes 107 times of original when heard by other, then the speed of each car is

Question 12Why does the Sun appear reddish early in the morning?

The values of two resistors are R, = (6 \pm 0.3) k2and R2 (10 0.2) k2. The percentage error inthe equivalent resistance when they are connectedin parallel is(1) 5.125%(2) 2%(3) 3.875%(4) 7%

Name a liquid whose mass density is less than that of water but is optically denser than water.

Why we take notation of SHE as H2/H+ Why not H+/H2 as it can act as both cathode and anode

what is diffraction and intereference of light?

A magnet oscillating in a horizontal plane has a time period of 2 sec at a place where the angle of dip is 30∘ and 3 sec at another place where the angle of dip is 60∘. The ratio of resultant magnetic fields at the two places is:

Are the ray PM and PT opposite rays? Give reasons for your answer.

Why is the mass of a body concentrated at the center of gravity?

a rod of length l and cross sectional area a lies along the x - axis between x = l and x = 2l. resistivity of rod varies according to law p = pnot(x/l). if the rod is subjected to potential difference v0, then current in the rod is

Rays parallel to the principal axis of a concave or convex mirror meet or appear to come from which point?

charge of 10micro coulomb is placed at the origin of x-y coordinate system. The potential difference between two points (0, a) and (a, 0) in volt will be

The frequency of a car horn encountered a change from 400 Hz to 500 Hz, when the car approaches a vertical wall. If the speed of sound is 330 m/s. Then the speed of car is _____ km/h.

The bulb in the circuit shown below does not glow. Which of the following labelled parts is responsible for this?

94. If the escape velocity at earth is 11.2km/s , then what will be the escape velocity of planet having mass 4 times of earth and gravitational acceleration equal to earth??

For the myopic eye, the defect is cured by using:

Two thin identical shape plano-convex lenses L1(μ1=1.4) and L2(μ2=1.5) with radius of curvature R=20 cm have been arranged as shown in figure.A parallel beam of light is incident on the system of the lenses, the position of image formed with respect to the common optical center is:

Two similar circular loops of radius R are lying concentrically with their planes at right angles to each other. The current flowing in them are 'i' and 'i root 3' respectively. The magnetic field at the centre of the coil is?

How much momentum will a dumbbell of mass 10 kg transfer to the floor if it falls from a height of 80 cm (assume that the dumbbell stops after hitting the ground)? Take g = 10 ms-2 .

Can you tell out of the following machines in which electromagnet is used?

standrad deviation short cut method formula proof

A solenoid has a core of a material with relative permeability 500. The winding of the solenoid are insulated from the core and carry current of 5 A. If the number of turns are 1000 per metre, what is the intensity of magnetization of the core?

If 3 bodies A, B and C are connected to each other, the temperature of body A is 23°C, B is at 119°C and C is at 78 °C, then from which body/bodies will the heat flow from?

U−235 requires a neutron to be bombarded into it to undergo fission because

Silver is the best conductor of electricity can you say why electric wires are not made up of silver?

The harnessing of which of the following leads to the destruction of large eco-systems ? (a) thermal power (b) tidal power (c) hydro power (d) geothermal power

An object of the height of 2 cm is placed perpendicular to the principal axis of a concave lens of the focal length of 12 cm. find the height of the image, if the object is placed at a distance of 8 cm from the lens?

Which of the following represents the current-time graph of a generator with slip rings?

List various fields where cryogenics can be used. Also, explain in brief how it finds its application.

The commercial unit of energy is : (a) watt (b) watt-hour (c) kilowatt-hour (d) kilo-joule

All formulas of chapter light reflection and refraction

The atomic numbers and mass numbers of X respectively ? 21884PO→X+42He

If the power of a lens is + 0.1 D and if the object of size 2 cm is placed 5 cm before the lens. Find the size and position of the image formed.

While calculating heat energy, what should be the unit of time? Second or hours?

The Figure shows a spherical concave mirror with its pole at (0,0) and principal axis along the x-axis. There is a point object located at (−40 cm,1 cm). Find the position of the image.

A material of resistivity ρ is formed in the shape of a truncated cone of altitude h. The top end has a radius "a" while bottom end has a radius "b". Assuming a uniform current density through any circular cross-section of the cone, find the resistance between the two ends.

A ray of light travelling in the air falls on the surface of a plastic slab at an angle 53° ( sin530 = 45) with the normal. The refractive index of plastic slab is 1.6. Calculate the angle of refraction.

In a block and tackle system consisting of 3 pulleys, a load of 75 kgf is raised with an effort of 25 kgf. Find : (i) the mechanical advantage, (ii) the velocity ratio, and (iii) the efficiency.

Q. At the place horizontal and vertical components of Earth's magnetic field are as follows BH = 1 G 10^° west of north Bv=1 G vertically downward then the dip angle and declination are respectively??