16569 + Interview Questions in Physics Page 28 InterviewSolution

1351.	The resistance of the meter bridge AB in given figure is 4Ω. With a cell of emf E=0.5 V and rheostat resistance Rh=2Ω the null point is obtained at some point J. When the cell is replaced by another one of emf E=E2 the same null point J is found for Rh=6Ω. The emf E2 is:
Answer» The resistance of the meter bridge $A B$ in given figure is $4 Ω$ . With a cell of emf $E = 0.5 V$ and rheostat resistance $R_{h} = 2 Ω$ the null point is obtained at some point $J$ . When the cell is replaced by another one of emf $E = E_{2}$ the same null point $J$ is found for $R_{h} = 6 Ω$ . The emf $E_{2}$ is:

Discussion

1352.	You are supplied with a number of 100Ω resistors. How could you combine some of these resistors to make a 250 Ω resistor?
Answer» You are supplied with a number of $100 Ω$ resistors. How could you combine some of these resistors to make a $250 Ω$ resistor?

Discussion

1353.	What does short circuiting of battery terminals mean?
Answer» What does short circuiting of battery terminals mean?

Discussion

1354.

A planet of mass M, has two natural satellites with masses m1 and m2. The radii of their circular orbits are R1 and R2 respectively. Ignore the gravitational force between the satellites. Define v1,L1,K1 and T1 to be respectively, the orbital speed, angular momentum, kinetic energy and time period of revolution of satellite 1; and v2,L2,K2 and T2 to be the corresponding quantities of satellite 2. Given m1/m2=2 and R1/R2=1/4, match the ratios in List - I to the numbers in List-II.List-IList-IIP. v1v21. 18Q. L1L22. 1R. K1K23. 2S. T1T24. 8

Answer»

A planet of mass M, has two natural satellites with masses $m_{1}$ and $m_{2}$ . The radii of their circular orbits are $R_{1}$ and $R_{2}$ respectively. Ignore the gravitational force between the satellites. Define $v_{1}, L_{1}, K_{1}$ and $T_{1}$ to be respectively, the orbital speed, angular momentum, kinetic energy and time period of revolution of satellite $1$ ; and $v_{2}, L_{2}, K_{2}$ and $T_{2}$ to be the corresponding quantities of satellite $2$ . Given $m_{1} / m_{2} = 2$ and $R_{1} / R_{2} = 1 / 4$ , match the ratios in List - I to the numbers in List-II.

List-I	List-II
P. $\frac{v_{1}}{v_{2}}$	1. $\frac{1}{8}$
Q. $\frac{L_{1}}{L_{2}}$	2. $1$
R. $\frac{K_{1}}{K_{2}}$	3. $2$
S. $\frac{T_{1}}{T_{2}}$	4. $8$

Discussion

1355.	Why do stars twinkle?
Answer» Why do stars twinkle?

Discussion

1356.	How to identify the combinations of resistors are in parallel or series while solving problems ?
Answer» How to identify the combinations of resistors are in parallel or series while solving problems ?

Discussion

1357.	A person cannot see distant objects clearly. His vision can be corrected by using the spectacles containing : (a) concave lenses (b) plane lenses (c) contact lenses (d) convex lenses
Answer» A person cannot see distant objects clearly. His vision can be corrected by using the spectacles containing : (a) concave lenses (b) plane lenses (c) contact lenses (d) convex lenses

Discussion

1358.	Define the following: 1. Magnetic field 2. Electromagnetic force 3. Direction of electromagnetic force
Answer» Define the following: 1. Magnetic field 2. Electromagnetic force 3. Direction of electromagnetic force

1358.

Define the following: 1. Magnetic field 2. Electromagnetic force 3. Direction of electromagnetic force

Answer»

Define the following:

1. Magnetic field

2. Electromagnetic force

3. Direction of electromagnetic force

Discussion

1359.	When two bodies A and B are brought in contact with each other, heat does not flow between them. When another body C is brought in contact with B, the heat starts flowing from C to B. After the heat flow stops, C is now brought into contact with A, then which of the following is correct?
Answer» When two bodies A and B are brought in contact with each other, heat does not flow between them. When another body C is brought in contact with B, the heat starts flowing from C to B. After the heat flow stops, C is now brought into contact with A, then which of the following is correct?

Discussion

1360.	a plano-convex lens (f=20cm) is silvered at the plane surface. Find the focal length of this new combination.
Answer» a plano-convex lens (f=20cm) is silvered at the plane surface. Find the focal length of this new combination.

Discussion

1361.	You have three resistors of values 2Ω,3Ω and 5Ω How will you join them so that the total resistance is less than 1Ω draw diagram and find the total resistance.
Answer» You have three resistors of values $2 Ω, 3 Ω$ and $5 Ω$ How will you join them so that the total resistance is less than $1 Ω$ draw diagram and find the total resistance.

Discussion

1362.	Which of these fractions of petroleum has the lowest boiling point?(a) heavy oil(b) gasoline(c) kerosene(d) petroleum gas
Answer» Which of these fractions of petroleum has the lowest boiling point? (a) heavy oil (b) gasoline (c) kerosene (d) petroleum gas

Discussion

1363.	Composition of the nuclei of two atomic species X and Y are given as under:Protons of X =6, Neutrons of X=6Protons of Y =6, Neutrons of Y=8Calculate the mass numbers of X and Y. What is the relation between the two species?
Answer» Composition of the nuclei of two atomic species X and Y are given as under: Protons of X =6, Neutrons of X=6 Protons of Y =6, Neutrons of Y=8 Calculate the mass numbers of X and Y. What is the relation between the two species?

Discussion

1364.	Heat of 360 joules is produced each second in a resistor of 10 ohms. The current passes from this resistor is ________ amperes.
Answer» Heat of 360 joules is produced each second in a resistor of 10 ohms. The current passes from this resistor is ________ amperes.

Discussion

1365.	In spite of having both magnitude and direction why is electric current a scalar quantity not a vector quantity.
Answer» In spite of having both magnitude and direction why is electric current a scalar quantity not a vector quantity.

Discussion

1366.	What is the near point or far point of normal eye?
Answer» What is the near point or far point of normal eye?

Discussion

1367.	5. Zener diodes are heavily doped but they have a very thin depletion region, why?
Answer» 5. Zener diodes are heavily doped but they have a very thin depletion region, why?

Discussion

1368.	24.Why if a water drop is dropped on a surface it gets the that type of shape
Answer» 24.Why if a water drop is dropped on a surface it gets the that type of shape

Discussion

1369.	At what height is the water going to turn a paddle wheel much quicker?
Answer» At what height is the water going to turn a paddle wheel much quicker?

Discussion

1370.	The mirror has been called 'a four-cornered god' because: i. it is square shaped ii. like God it watches you unbiased and fair from all four angles iii. it reflects back all that it sees iv. it never stops reflecting
Answer» The mirror has been called 'a four-cornered god' because: i. it is square shaped ii. like God it watches you unbiased and fair from all four angles iii. it reflects back all that it sees iv. it never stops reflecting

1370.

The mirror has been called 'a four-cornered god' because: i. it is square shaped ii. like God it watches you unbiased and fair from all four angles iii. it reflects back all that it sees iv. it never stops reflecting

Answer»

The mirror has been
called 'a
four-cornered god' because:

i.
it is square shaped

ii.
like God it watches you unbiased and fair from all four angles

iii.
it reflects back all that it sees

iv.
it never stops reflecting

Discussion

1371.	At what distance from a concave mirror of focal length 10cm should an object 2cm be long placed in order to get an erect image of 6 cm tall ?
Answer» At what distance from a concave mirror of focal length 10cm should an object 2cm be long placed in order to get an erect image of 6 cm tall ?

Discussion

1372.	A light-ray behaves as a ___
Answer» A light-ray behaves as a ___

Discussion

1373.	In the circuit shown , the resistance of voltmeter is 10,000 Ω and that of ammeter is 20 Ω. The ammeter reading is 0.10 A and voltmeter reading is 12 V. Then value of R is equal to
Answer» In the circuit shown , the resistance of voltmeter is $10, 000 Ω$ and that of ammeter is $20 Ω$ . The ammeter reading is $0.10 A$ and voltmeter reading is $12 V$ . Then value of $R$ is equal to

Discussion

1374.	(a)What are the anode and cathode reaction of dry ce ? (b)Is it a primary or secondary cell? (c)It can be charged or not
Answer» (a)What are the anode and cathode reaction of dry ce ? (b)Is it a primary or secondary cell? (c)It can be charged or not

Discussion

1375.	ntThe length of a magnet is large compared to its width and breadth.The time period of its oscillation in a vibration magnetometer is 2 sec.The magnet is cut along its length into three equal parts.These parts are then placed on each other with their like poles together.The time period of this combination will ben nta)2 secn ntb)2/3 secn ntc)2sqrt3 secn ntd)2/sqrt3 secn
Answer» ntThe length of a magnet is large compared to its width and breadth.The time period of its oscillation in a vibration magnetometer is 2 sec.The magnet is cut along its length into three equal parts.These parts are then placed on each other with their like poles together.The time period of this combination will ben nta)2 secn ntb)2/3 secn ntc)2sqrt3 secn ntd)2/sqrt3 secn

Discussion

1376.	If v is escape velocity and v is orbital velocity of asatellite for orbit close to the earth's surface, thenthese are related by (1) vo -2ve (2) vo - ve (3) ve2Vo (4) v. 2vo
Answer» If v is escape velocity and v is orbital velocity of asatellite for orbit close to the earth's surface, thenthese are related by (1) vo -2ve (2) vo - ve (3) ve2Vo (4) v. 2vo

Discussion

1377.

Refractive index of media A, B, C and D are: A 1.33 B 1.52 C 1.44 D 1.65 In which of the four media is the speed of light (i) maximum (ii) minimum?

Answer» Refractive index of media A, B, C and D are:

A	1.33
B	1.52
C	1.44
D	1.65

In which of the four media is the speed of light (i) maximum (ii) minimum?

Discussion

1378.	why does curent flow from positive to negative as the electron should move from negative to positive pole.
Answer» why does curent flow from positive to negative as the electron should move from negative to positive pole.

Discussion

1379.	Give two characteristics of the image formed by a concave lens.
Answer» Give two characteristics of the image formed by a concave lens.

Discussion

1380.	Which of the following determines the direction of magnetic field due to a current carrying conductor?
Answer» Which of the following determines the direction of magnetic field due to a current carrying conductor?

Discussion

1381.	What happens when phase wire touches another phase wire.
Answer» What happens when phase wire touches another phase wire.

Discussion

1382.	A lead ball at 30∘C is dropped from a height of 6.2 km. The ball is heated due to the air resistance and it completely melts just before reaching the ground. The molten substance falls slowly on the ground. Calculate the latent heat of fusion of lead. Specific heat capacity of lead = 126 J kg−1 ∘C−1 and melting point of lead = 330∘C. Assume that any mechanical energy lost is used to heat the ball. Use g = 10 ms−2.
Answer» A lead ball at $30^{\circ} C$ is dropped from a height of $6.2 k m$ . The ball is heated due to the air resistance and it completely melts just before reaching the ground. The molten substance falls slowly on the ground. Calculate the latent heat of fusion of lead. Specific heat capacity of lead = $126 J k g^{- 1}^{\circ} C^{- 1}$ and melting point of lead = $330^{\circ} C$ . Assume that any mechanical energy lost is used to heat the ball. Use $g$ = $10 m s^{- 2}$ .

Discussion

1383.	How is difference of pressure at two points in an electric circuit
Answer» How is difference of pressure at two points in an electric circuit

Discussion

1384.	The focal length of field achromatic combination of a telescope is 90 cm. The dispersive powers of lenses are 0.012 and 0.018 respectively. Their focal lengths will be
Answer» The focal length of field achromatic combination of a telescope is 90 cm. The dispersive powers of lenses are 0.012 and 0.018 respectively. Their focal lengths will be

Discussion

1385.	If a bar magnet is brought closer to another bar magnet's head. It was observed that they repel each other. Which of the following can be true?
Answer» If a bar magnet is brought closer to another bar magnet's head. It was observed that they repel each other. Which of the following can be true?

1385.

If a bar magnet is brought closer to another bar magnet's head. It was observed that they repel each other. Which of the following can be true?

Answer»

If a bar magnet is brought closer to another bar magnet's head. It was observed that they repel each other. Which of the following can be true?

Discussion

1386.	Question 19In which of the following, the image of an object placed at infinity will be highly diminished and point sized?(a) Concave mirror only(b) Convex mirror only(c) Convex lens only(d) Concave mirror, convex mirror, concave lens and convex lens
Answer» Question 19 In which of the following, the image of an object placed at infinity will be highly diminished and point sized? (a) Concave mirror only (b) Convex mirror only (c) Convex lens only (d) Concave mirror, convex mirror, concave lens and convex lens

Discussion

1387.	27. electric resistance of a certain wire of resistance R ,if its length and radius are both doubled then the resistance will be? Explain in detail
Answer» 27. electric resistance of a certain wire of resistance R ,if its length and radius are both doubled then the resistance will be? Explain in detail

Discussion

1388.	For a step-up transformer
Answer» For a step-up transformer

Discussion

1389.	A beam of parallel light rays is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the diagram below : Which of the following could be inside the box ? (a) a rectangular glass block (b) a concave lens (c) a convex lens (d) a glass prism
Answer» A beam of parallel light rays is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the diagram below : Which of the following could be inside the box ? (a) a rectangular glass block (b) a concave lens (c) a convex lens (d) a glass prism

1389.

A beam of parallel light rays is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the diagram below : Which of the following could be inside the box ? (a) a rectangular glass block (b) a concave lens (c) a convex lens (d) a glass prism

Answer»

A beam of parallel light rays is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the diagram below : Which of the following could be inside the box ? (a) a rectangular glass block (b) a concave lens (c) a convex lens (d) a glass prism

Discussion

1390.	Electrolytic conduction differs from metallic conduction in that in the case of electrolytic conduction A)The resistance increases with increasing temperatureB)The resistance decreases with increasing temperatureC)The flow of current does not generate heatD)The resistance is independent of the length of the conductor
Answer» Electrolytic conduction differs from metallic conduction in that in the case of electrolytic conduction A)The resistance increases with increasing temperature B)The resistance decreases with increasing temperature C)The flow of current does not generate heat D)The resistance is independent of the length of the conductor

Discussion

1391.	(1) 25 m/s(2) 91 km/h(3) 26 km/h(4) 26 m/s15. Figure shows two ships moving in x-y plane withvelocities V and V. The ships move such that BAB\ast always remains north of A. The ratio Is equal toABW-- E20BAVA(2) sine(1) cose(4) cosece(3) seceNS
Answer» (1) 25 m/s(2) 91 km/h(3) 26 km/h(4) 26 m/s15. Figure shows two ships moving in x-y plane withvelocities V and V. The ships move such that BAB\ast always remains north of A. The ratio Is equal toABW-- E20BAVA(2) sine(1) cose(4) cosece(3) seceNS

Discussion

1392.	Which of the factors varies when sound propagates through air molecules?
Answer» Which of the factors varies when sound propagates through air molecules?

Discussion

1393.	A guitar produces a sound which has a frequency of 300 Hz and a wavelength of 1.3 m. Calculate the speed with which this sound travels.
Answer» A guitar produces a sound which has a frequency of $300 H z$ and a wavelength of $1.3 m$ . Calculate the speed with which this sound travels.

Discussion

1394.	Is it always necessary that when a charged particle moves, the trajectory having helical path is supposed to be along X axis?
Answer» Is it always necessary that when a charged particle moves, the trajectory having helical path is supposed to be along X axis?

Discussion

1395.	ntThe gravitational potential energy of a body at a distance r from the centre of the earth is U. It's weight at a distance 2r from the centre of the earth in terms of U is ?n
Answer» ntThe gravitational potential energy of a body at a distance r from the centre of the earth is U. It's weight at a distance 2r from the centre of the earth in terms of U is ?n

Discussion

1396.	In the process of light entering our eye and forming an image at retina, at which interface the maximum refraction takes place?
Answer» In the process of light entering our eye and forming an image at retina, at which interface the maximum refraction takes place?

Discussion

1397.	When live wire comes in direct contact with the neutral wire, then
Answer» When live wire comes in direct contact with the neutral wire, then

Discussion

1398.	Two identical batteries, each of 2 V and internalresistance 1Ω are available to produce heat in a resistor R=0.5Ω by passing current through it.The maximum heating power that can be developed across R using these batteries is
Answer» Two identical batteries, each of 2 V and internalresistance 1Ω are available to produce heat in a resistor R=0.5Ω by passing current through it.The maximum heating power that can be developed across R using these batteries is

Discussion

1399.	Which is conservation law of nature ?a) Law of conservation of chargeb)Law of conservation of linear momentumc)Law of conservation of energyd) All of these
Answer» Which is conservation law of nature ? a) Law of conservation of charge b)Law of conservation of linear momentum c)Law of conservation of energy d) All of these

Discussion

1400.	The variation of refractive index of a crown glass thin prism with wavelength of the incident light is shown. Which of the following graphs is the correct one, if Dm is the angle of minimum deviation?
Answer» The variation of refractive index of a crown glass thin prism with wavelength of the incident light is shown. Which of the following graphs is the correct one, if $D_{m}$ is the angle of minimum deviation?

Discussion

Explore topic-wise InterviewSolutions in .

The resistance of the meter bridge AB in given figure is 4Ω. With a cell of emf E=0.5 V and rheostat resistance Rh=2Ω the null point is obtained at some point J. When the cell is replaced by another one of emf E=E2 the same null point J is found for Rh=6Ω. The emf E2 is:

You are supplied with a number of 100Ω resistors. How could you combine some of these resistors to make a 250 Ω resistor?

What does short circuiting of battery terminals mean?

Why do stars twinkle?

How to identify the combinations of resistors are in parallel or series while solving problems ?

A person cannot see distant objects clearly. His vision can be corrected by using the spectacles containing : (a) concave lenses (b) plane lenses (c) contact lenses (d) convex lenses

Define the following: 1. Magnetic field 2. Electromagnetic force 3. Direction of electromagnetic force

When two bodies A and B are brought in contact with each other, heat does not flow between them. When another body C is brought in contact with B, the heat starts flowing from C to B. After the heat flow stops, C is now brought into contact with A, then which of the following is correct?

a plano-convex lens (f=20cm) is silvered at the plane surface. Find the focal length of this new combination.

You have three resistors of values 2Ω,3Ω and 5Ω How will you join them so that the total resistance is less than 1Ω draw diagram and find the total resistance.

Which of these fractions of petroleum has the lowest boiling point?(a) heavy oil(b) gasoline(c) kerosene​(d) petroleum gas

Composition of the nuclei of two atomic species X and Y are given as under:Protons of X =6, Neutrons of X=6Protons of Y =6, Neutrons of Y=8Calculate the mass numbers of X and Y. What is the relation between the two species?

Heat of 360 joules is produced each second in a resistor of 10 ohms. The current passes from this resistor is ________ amperes.

In spite of having both magnitude and direction why is electric current a scalar quantity not a vector quantity.

What is the near point or far point of normal eye?

5. Zener diodes are heavily doped but they have a very thin depletion region, why?

24.Why if a water drop is dropped on a surface it gets the that type of shape

At what height is the water going to turn a paddle wheel much quicker?

The mirror has been called 'a four-cornered god' because: i. it is square shaped ii. like God it watches you unbiased and fair from all four angles iii. it reflects back all that it sees iv. it never stops reflecting

At what distance from a concave mirror of focal length 10cm should an object 2cm be long placed in order to get an erect image of 6 cm tall ?

A light-ray behaves as a ___

In the circuit shown , the resistance of voltmeter is 10,000 Ω and that of ammeter is 20 Ω. The ammeter reading is 0.10 A and voltmeter reading is 12 V. Then value of R is equal to

(a)What are the anode and cathode reaction of dry ce ? (b)Is it a primary or secondary cell? (c)It can be charged or not

If v is escape velocity and v is orbital velocity of asatellite for orbit close to the earth's surface, thenthese are related by (1) vo -2ve (2) vo - ve (3) ve2Vo (4) v. 2vo

Refractive index of media A, B, C and D are: A 1.33 B 1.52 C 1.44 D 1.65 In which of the four media is the speed of light (i) maximum (ii) minimum?

why does curent flow from positive to negative as the electron should move from negative to positive pole.

Give two characteristics of the image formed by a concave lens.

Which of the following determines the direction of magnetic field due to a current carrying conductor?

What happens when phase wire touches another phase wire.

How is difference of pressure at two points in an electric circuit

The focal length of field achromatic combination of a telescope is 90 cm. The dispersive powers of lenses are 0.012 and 0.018 respectively. Their focal lengths will be

If a bar magnet is brought closer to another bar magnet's head. It was observed that they repel each other. Which of the following can be true?

Question 19In which of the following, the image of an object placed at infinity will be highly diminished and point sized?(a) Concave mirror only(b) Convex mirror only(c) Convex lens only(d) Concave mirror, convex mirror, concave lens and convex lens

27. electric resistance of a certain wire of resistance R ,if its length and radius are both doubled then the resistance will be? Explain in detail

For a step-up transformer

(1) 25 m/s(2) 91 km/h(3) 26 km/h(4) 26 m/s15. Figure shows two ships moving in x-y plane withvelocities V and V. The ships move such that BAB\ast always remains north of A. The ratio Is equal toABW-- E20BAVA(2) sine(1) cose(4) cosece(3) seceNS

Which of the factors varies when sound propagates through air molecules?

A guitar produces a sound which has a frequency of 300 Hz and a wavelength of 1.3 m. Calculate the speed with which this sound travels.

Is it always necessary that when a charged particle moves, the trajectory having helical path is supposed to be along X axis?

ntThe gravitational potential energy of a body at a distance r from the centre of the earth is U. It's weight at a distance 2r from the centre of the earth in terms of U is ?n

In the process of light entering our eye and forming an image at retina, at which interface the maximum refraction takes place?

When live wire comes in direct contact with the neutral wire, then

Two identical batteries, each of 2 V and internalresistance 1Ω are available to produce heat in a resistor R=0.5Ω by passing current through it.The maximum heating power that can be developed across R using these batteries is

Which is conservation law of nature ?a) Law of conservation of chargeb)Law of conservation of linear momentumc)Law of conservation of energyd) All of these

The variation of refractive index of a crown glass thin prism with wavelength of the incident light is shown. Which of the following graphs is the correct one, if Dm is the angle of minimum deviation?

Which of these fractions of petroleum has the lowest boiling point?(a) heavy oil(b) gasoline(c) kerosene(d) petroleum gas