50278 + Interview Questions in Physics

1.	A coil of inductance L is carrying a steady current i. What is the nature of its stored energy?
Answer» A coil of inductance L is carrying a steady current i. What is the nature of its stored energy?

Discussion

2.	The retardation of the object projected vertically upwards is how much? Does it depends on mass or all objects have same velocity while coming down?
Answer» The retardation of the object projected vertically upwards is how much? Does it depends on mass or all objects have same velocity while coming down?

Discussion

3.	A steel blade float on the surface of pure water when detergent is added,it sinks.why?
Answer» A steel blade float on the surface of pure water when detergent is added,it sinks.why?

Discussion

4.	We know that there are many application of Doppler's Effect , SONAR system is one of them.This system is used to detect any obstacle around the ship, so as we know that this system was also used in Titanic Ship. Titanic was destroyed due to its dreadful collision with huge ice Berg! Even if there was SONAR system in the ship it sink. Wasn't it was able to detect that gigantic ice Berg?
Answer» We know that there are many application of Doppler's Effect , SONAR system is one of them.This system is used to detect any obstacle around the ship, so as we know that this system was also used in Titanic Ship. Titanic was destroyed due to its dreadful collision with huge ice Berg! Even if there was SONAR system in the ship it sink. Wasn't it was able to detect that gigantic ice Berg?

Discussion

5.	A uniform chain of length L has one of its ends attached to the wall at point A, while 3L4 length of the chain is lying on the table as shown in figure. Then, minimum co-efficient of static friction between table and chain, so that the chain remains in equilibrium is
Answer» A uniform chain of length $L$ has one of its ends attached to the wall at point A, while $\frac{3 L}{4}$ length of the chain is lying on the table as shown in figure. Then, minimum co-efficient of static friction between table and chain, so that the chain remains in equilibrium is

Discussion

6.	A fan is revolving with an angular speed of 120 rpm. Suddenly a boy switches off the fan and it eventually comes to rest by making 30 revolutions in 2 mins. The average angular velocity of the fan is
Answer» A fan is revolving with an angular speed of $120 rpm$ . Suddenly a boy switches off the fan and it eventually comes to rest by making 30 revolutions in 2 mins. The average angular velocity of the fan is

Discussion

7.	The nuclei of two radioactive isotopes of same substance A236 and A234 are present in the ratio 4 : 1 in an ore obtained from Mars. Their half lives are 30 min and 60 min respectively. Both isotopes are alpha emitters and the activity of the isotope with half life 30min is one Rutherford. Calculate after how much time (in min) their activities will become identical.
Answer» The nuclei of two radioactive isotopes of same substance $A^{236}$ and $A^{234}$ are present in the ratio 4 : 1 in an ore obtained from Mars. Their half lives are $30 min$ and $60 min$ respectively. Both isotopes are alpha emitters and the activity of the isotope with half life $30 min$ is one Rutherford. Calculate after how much time (in min) their activities will become identical.

Discussion

8.	When we kick a stone ,we get hurt.due to which one of the following properties of stone it happens.. 1.inertia 2..velocity 3. Reaction 4 .. momentum.. plz give proper explanation..😀
Answer» When we kick a stone ,we get hurt.due to which one of the following properties of stone it happens.. 1.inertia 2..velocity 3. Reaction 4 .. momentum.. plz give proper explanation..😀

Discussion

9.	In a vernier caliper, 10 vernier scale divisions are equal to 9 main scale divisions. One main scale division is 1 mm. The device has some zero error as shown in the figure (a). When a cylinder of diameter D is inserted between them, the reading of scale is shown in figure (b). Then, the diameter of the cylinder in cm is
Answer» In a vernier caliper, 10 vernier scale divisions are equal to 9 main scale divisions. One main scale division is 1 mm. The device has some zero error as shown in the figure (a). When a cylinder of diameter D is inserted between them, the reading of scale is shown in figure (b). Then, the diameter of the cylinder in cm is

Discussion

10.	Find the acceleration of block of mass m w.r.t ground if acceleration of M is b=4 m/s2. (Assume all surfaces to be smooth and string inextensible.)
Answer» Find the acceleration of block of mass $m$ w.r.t ground if acceleration of $M$ is $b = 4 m / s^{2}$ . (Assume all surfaces to be smooth and string inextensible.)

Discussion

11.	Acceleration÷time is called as ___________.
Answer» Acceleration÷time is called as ___________.

Discussion

12.	In magnetic field of electric current ,magnetic induction along the axis of long straight solenoid According to another circuit law $B.dl=u0 (nLI) Here current flowing through the rectangular path 'nl' times taken ,why
Answer» In magnetic field of electric current ,magnetic induction along the axis of long straight solenoid According to another circuit law $B.dl=u₀(nLI) Here current flowing through the rectangular path 'nl' times taken ,why

12.

In magnetic field of electric current ,magnetic induction along the axis of long straight solenoid According to another circuit law $B.dl=u0 (nLI) Here current flowing through the rectangular path 'nl' times taken ,why

Answer»

In magnetic field of electric current ,magnetic induction along the axis of long straight solenoid

According to another circuit law

$B.dl=u₀(nLI)

Here current flowing through the rectangular path 'nl' times taken ,why

Discussion

13.	The temperatures of two bodies A and B are 727o C and 127o C. The ratio of rate of emission of radiations will be
Answer» The temperatures of two bodies A and B are $727^{o} C$ and $127^{o} C$ . The ratio of rate of emission of radiations will be

Discussion

14.	What is pseudo force in nature? What is its magnitude and direction
Answer» What is pseudo force in nature? What is its magnitude and direction

Discussion

15.	A thin wire has a length of 21.7 cm and radius 0.46 mm.Calculatethe volume of the wire to correct number of significant figures
Answer» A thin wire has a length of 21.7 cm and radius 0.46 mm.Calculatethe volume of the wire to correct number of significant figures

Discussion

16.	What is the required condition, if the light incident on one face, does not emerge from the other face ?
Answer» What is the required condition, if the light incident on one face, does not emerge from the other face ?

Discussion

17.	Two pure inductors are connected in series, if their self inductance is L. Find the total inductance
Answer» Two pure inductors are connected in series, if their self inductance is L. Find the total inductance

Discussion

18.	The area of right triangle is 150cm square. If it's altitude exceed the Base by 5cm . Calculate perimeter of triangle
Answer» The area of right triangle is 150cm square. If it's altitude exceed the Base by 5cm . Calculate perimeter of triangle

Discussion

19.	Difference between centre of mass and centre of gravity ?
Answer» Difference between centre of mass and centre of gravity ?

Discussion

20.	The distance between two consecutive crests in a wave train produced in a string is 5 cm. If 2 complete waves pass through any point per second, the velocity of the wave is [CPMT 1990]
Answer» The distance between two consecutive crests in a wave train produced in a string is 5 cm. If 2 complete waves pass through any point per second, the velocity of the wave is [CPMT 1990]

20.

The distance between two consecutive crests in a wave train produced in a string is 5 cm. If 2 complete waves pass through any point per second, the velocity of the wave is [CPMT 1990]

Answer»

The distance between two consecutive crests in a wave train produced in a

string is 5 cm. If 2 complete waves pass through any point per second, the

velocity of the wave is [CPMT 1990]

Discussion

21.	A spacecraft of mass 'M' explodes into two parts when its velocity is 'V'. After the explosion, one part of mass 'm' is left stationary. What is the velocity of the other part?
Answer» A spacecraft of mass 'M' explodes into two parts when its velocity is 'V'. After the explosion, one part of mass 'm' is left stationary. What is the velocity of the other part?

Discussion

22.	What is geostationary satellite and what is the time period taken by it orbiting the earth?
Answer» What is geostationary satellite and what is the time period taken by it orbiting the earth?

Discussion

23.	How many electrons are flowing per second through a section of a conductor corresponding to current of 1A?
Answer» How many electrons are flowing per second through a section of a conductor corresponding to current of 1A?

Discussion

24.	What is null vector?
Answer» What is null vector?

Discussion

25.	Can two equi potential surfaces interest each other? Give reasons . Two charges -q and +q are located at points A(0,0,-q) and B(0,0,+a) respectively. How much work is done in moving a test charge from point P(7,0,0) to Q(-3,0,0)?
Answer» Can two equi potential surfaces interest each other? Give reasons . Two charges -q and +q are located at points A(0,0,-q) and B(0,0,+a) respectively. How much work is done in moving a test charge from point P(7,0,0) to Q(-3,0,0)?

Discussion

26.	A coil having inductance 2.0 H and resistance 20 Ω is connected to a battery of emf 4.0 V. Find (a) the current at the instant 0.20 s after the connection is made and (b) the magnetic field energy at this instant.
Answer» A coil having inductance 2.0 H and resistance $20 Ω$ is connected to a battery of emf 4.0 V. Find (a) the current at the instant 0.20 s after the connection is made and (b) the magnetic field energy at this instant.

Discussion

27.	Why does bluish colour predominate in a clear sky?
Answer» Why does bluish colour predominate in a clear sky?

Discussion

28.	A metal stick of mass 1 kg and length 1 metre is held vertically with one end on the floor and is then allowed to fall. All values are in SI units. Take approximations. Column-IColumn-II(a) Initial mechanical energy(p)5.425(b)(Angular velocity) 2 just before hitting the ground(q) 29.429(c) Linear velocity of the free end just before hitting the ground(r) 4.9(d) Moment of inertia(s) 0.333
Answer» A metal stick of mass $1$ kg and length 1 metre is held vertically with one end on the floor and is then allowed to fall. All values are in SI units. Take approximations. $\begin{matrix} Column-I & Column-II (a) Initial mechanical energy & (p) 5.425 {(b)(Angular velocity)}^{2} just before hitting the ground & (q) 29.429 (c) Linear velocity of the free end just before hitting the ground & (r) 4.9 (d) Moment of inertia & (s) 0.333 \end{matrix}$

Discussion

29.	A particle p is moving in a circle of radius 'd' with a uniform speed v. C is the centre of the circle and AB is a diameter. When passing through B the angular velocity of P about A and C are in the ratio
Answer» A particle p is moving in a circle of radius 'd' with a uniform speed v. C is the centre of the circle and AB is a diameter. When passing through B the angular velocity of P about A and C are in the ratio

Discussion

30.	10,000 small balls, each weighing 1 gm , strike one square cm of area per second with a velocity 100 m/s in a normal direction and rebound with the same velocity. The value of pressure on the surface will be
Answer» $10, 000$ small balls, each weighing $1 g m$ , strike one square cm of area per second with a velocity $100 m / s$ in a normal direction and rebound with the same velocity. The value of pressure on the surface will be

Discussion

31.	A charge Q is to be divided into two parts q and (Q-q) such that the force between them is maximum at a certain distance. The value of q is
Answer» A charge Q is to be divided into two parts q and (Q-q) such that the force between them is maximum at a certain distance. The value of q is

Discussion

32.	If the terminal speed of a sphere of gold (density = 19.5 g/cm3) is 0.2 m/s in a viscous liquid (density = 1.5 g/cm3). Find the terminal speed of a sphere of silver (density =10.5 g/cm3) of the same size in the same liquid.
Answer» If the terminal speed of a sphere of gold (density = $19.5 {g/cm}^{3})$ is $0.2 m/s$ in a viscous liquid (density = $1.5 {g/cm}^{3}$ ). Find the terminal speed of a sphere of silver (density $= 10.5 {g/cm}^{3})$ of the same size in the same liquid.

Discussion

33.	A ball of mass (m) 0.5 kg is attached to the end of a string having length (l) 0.5m. The ball is rotated on a horizontal circular path about vertical axis. The maximum tension that the string can bear is 324 N. The maximum possible value of angular velocity of ball (in rad/s) is
Answer» A ball of mass (m) 0.5 kg is attached to the end of a string having length (l) 0.5m. The ball is rotated on a horizontal circular path about vertical axis. The maximum tension that the string can bear is 324 N. The maximum possible value of angular velocity of ball (in rad/s) is

Discussion

34.	Water falls without splashing at a rate of 0.250 L/s from a height of 2.60 m into a 0.750 kg bucket on a scale. If the bucket is originally empty , what does the scale read 3 s after water starts to accumulate in it.
Answer» Water falls without splashing at a rate of 0.250 L/s from a height of 2.60 m into a 0.750 kg bucket on a scale. If the bucket is originally empty , what does the scale read 3 s after water starts to accumulate in it.

Discussion

35.	When two ends of a rod wrapped with cotton are maintained at different temperatures and after some time every point of the rod attains a constant temperature, then
Answer» When two ends of a rod wrapped with cotton are maintained at different temperatures and after some time every point of the rod attains a constant temperature, then

35.

When two ends of a rod wrapped with cotton are maintained at different temperatures and after some time every point of the rod attains a constant temperature, then

Answer»

When two ends of a rod wrapped with cotton are maintained at different temperatures and after some time every point of the rod attains a constant temperature, then

Discussion

36.	A calorimeter of water equivalent 15g contains 165g of water at 25∘C. Steam at 100∘C is passed through the water for some time. The temperature is increased to 30∘C and the mass of the calorimeter and its contents is increased by 1.5 g. Calculate the latent heat of vaporization of water. Heat capacity of water is 1 cal/g∘C
Answer» A calorimeter of water equivalent 15g contains 165g of water at $25^{\circ} C$ . Steam at $100^{\circ} C$ is passed through the water for some time. The temperature is increased to $30^{\circ} C$ and the mass of the calorimeter and its contents is increased by 1.5 g. Calculate the latent heat of vaporization of water. Heat capacity of water is $1 c a l / g^{\circ} C$

Discussion

37.	Which of the following equipment is used to harness solar energy?
Answer» Which of the following equipment is used to harness solar energy?

Discussion

38.	A steel wire fixed at both ends has a fundamentd: frequency of 200 Hz. A person can hear sound maximum frequency 14 kHz. What is the highest harmonic that can be played on this string which is audible to the person ?
Answer» A steel wire fixed at both ends has a fundamentd: frequency of 200 Hz. A person can hear sound maximum frequency 14 kHz. What is the highest harmonic that can be played on this string which is audible to the person ?

Discussion

39.	The frequency of one of the lines in Paschen series of hydrogen atom is 2.340 ×1011 Hz. The quantum number n2 which produces this transition is:
Answer» The frequency of one of the lines in Paschen series of hydrogen atom is $2.340 \times 10^{11}$ Hz. The quantum number $n_{2}$ which produces this transition is:

Discussion

40.	If a line in the ZX-plane makes an angle 60o with Z-axis, the direction cosines of this line are:
Answer» If a line in the ZX-plane makes an angle 60^o with Z-axis, the direction cosines of this line are:

Discussion

41.	The linear momentum of an electron revolving in the 2nd Bohr orbit is given by p=Kh where, h is the Planck's Constant. Predict the radius of the orbit.
Answer» The linear momentum of an electron revolving in the $2^{n d}$ Bohr orbit is given by $p = K h$ where, $h$ is the Planck's Constant. Predict the radius of the orbit.

Discussion

42.	Calculate the freezing point of a solution containing 60g of glucose (Molar mass = 180 g Mol−1) in 250 g of water. (kf of water=1.86 K kg mol−1)
Answer» Calculate the freezing point of a solution containing 60g of glucose (Molar mass = 180 g $M o l^{- 1})$ in 250 g of water. $(k_{f} o f w a t e r = 1.86 K k g m o l^{- 1})$

Discussion

43.	A thief with a box of 25kg jumps from a tall building in the downward direction. What will be the weight of the box experienced by the the if during downward fall?. Justify
Answer» A thief with a box of 25kg jumps from a tall building in the downward direction. What will be the weight of the box experienced by the the if during downward fall?. Justify

Discussion

44.	How many significant figures are there in 4200 kg?
Answer» How many significant figures are there in 4200 kg?

Discussion

45.	Let ωH and ωE respectively be the angular speeds of the hour hand of a watch and that of the earth around its own axis. Compare the angular speeds of the earth and hour hand of a watch.
Answer» Let ω_H and ω_E respectively be the angular speeds of the hour hand of a watch and that of the earth around its own axis. Compare the angular speeds of the earth and hour hand of a watch.

Discussion

46.	If the straight line y=mx+c passes through the points (3,-4) and (-1,2) then value of m is
Answer» If the straight line y=mx+c passes through the points (3,-4) and (-1,2) then value of m is

Discussion

47.	What is the wavelength of a photon that has energy of 5.25 x 10-19J?
Answer» What is the wavelength of a photon that has energy of 5.25 x 10^-19J?

Discussion

48.	Assertion : Photoelectric effect demonstrates the wave nature of light. Reason : The number of photoelectrons is directly proportional to the frequency of light.
Answer» Assertion : Photoelectric effect demonstrates the wave nature of light. Reason : The number of photoelectrons is directly proportional to the frequency of light.

Discussion

49.	A dielectric slab of dielectric constant k=5 is placed between plates of parallel plate capacitor, thickness of slab is 30% of plate spacing & its area is same as that of the plates, new capacitance is C′ & old capacitance was C. The ratio C′C is approximately equal to
Answer» A dielectric slab of dielectric constant $k = 5$ is placed between plates of parallel plate capacitor, thickness of slab is $30$ % of plate spacing & its area is same as that of the plates, new capacitance is $C^{'}$ & old capacitance was $C$ . The ratio $\frac{C^{'}}{C}$ is approximately equal to

Discussion

50.	Figure 17.16 shows the P - V diagram for a fixed mass of an ideal gas undergoing cyclic process. AB represents isothermal process and CA represents adiabatic process. Which of the graphs shown in Fig. 17.17 represents the P - T diagram of the cyclic process ?
Answer» Figure 17.16 shows the P - V diagram for a fixed mass of an ideal gas undergoing cyclic process. AB represents isothermal process and CA represents adiabatic process. Which of the graphs shown in Fig. 17.17 represents the P - T diagram of the cyclic process ?

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A coil of inductance L is carrying a steady current i. What is the nature of its stored energy?

The retardation of the object projected vertically upwards is how much? Does it depends on mass or all objects have same velocity while coming down?

A steel blade float on the surface of pure water when detergent is added,it sinks.why?

A uniform chain of length L has one of its ends attached to the wall at point A, while 3L4 length of the chain is lying on the table as shown in figure. Then, minimum co-efficient of static friction between table and chain, so that the chain remains in equilibrium is

A fan is revolving with an angular speed of 120 rpm. Suddenly a boy switches off the fan and it eventually comes to rest by making 30 revolutions in 2 mins. The average angular velocity of the fan is

When we kick a stone ,we get hurt.due to which one of the following properties of stone it happens.. 1.inertia 2..velocity 3. Reaction 4 .. momentum.. plz give proper explanation..😀

Find the acceleration of block of mass m w.r.t ground if acceleration of M is b=4 m/s2. (Assume all surfaces to be smooth and string inextensible.)

Acceleration÷time is called as ___________.

In magnetic field of electric current ,magnetic induction along the axis of long straight solenoid According to another circuit law $B​​​​.dl=u0 (nLI) Here current flowing through the rectangular path 'nl' times taken ,why

The temperatures of two bodies A and B are 727o C and 127o C. The ratio of rate of emission of radiations will be

What is pseudo force in nature? What is its magnitude and direction

A thin wire has a length of 21.7 cm and radius 0.46 mm.Calculatethe volume of the wire to correct number of significant figures

What is the required condition, if the light incident on one face, does not emerge from the other face ?

Two pure inductors are connected in series, if their self inductance is L. Find the total inductance

The area of right triangle is 150cm square. If it's altitude exceed the Base by 5cm . Calculate perimeter of triangle

Difference between centre of mass and centre of gravity ?

The distance between two consecutive crests in a wave train produced in a string is 5 cm. If 2 complete waves pass through any point per second, the velocity of the wave is [CPMT 1990]

A spacecraft of mass 'M' explodes into two parts when its velocity is 'V'. After the explosion, one part of mass 'm' is left stationary. What is the velocity of the other part?

What is geostationary satellite and what is the time period taken by it orbiting the earth?

How many electrons are flowing per second through a section of a conductor corresponding to current of 1A?

What is null vector?

Can two equi potential surfaces interest each other? Give reasons . Two charges -q and +q are located at points A(0,0,-q) and B(0,0,+a) respectively. How much work is done in moving a test charge from point P(7,0,0) to Q(-3,0,0)?

A coil having inductance 2.0 H and resistance 20 Ω is connected to a battery of emf 4.0 V. Find (a) the current at the instant 0.20 s after the connection is made and (b) the magnetic field energy at this instant.

Why does bluish colour predominate in a clear sky?

A particle p is moving in a circle of radius 'd' with a uniform speed v. C is the centre of the circle and AB is a diameter. When passing through B the angular velocity of P about A and C are in the ratio

10,000 small balls, each weighing 1 gm , strike one square cm of area per second with a velocity 100 m/s in a normal direction and rebound with the same velocity. The value of pressure on the surface will be

A charge Q is to be divided into two parts q and (Q-q) such that the force between them is maximum at a certain distance. The value of q is

If the terminal speed of a sphere of gold (density = 19.5 g/cm3) is 0.2 m/s in a viscous liquid (density = 1.5 g/cm3). Find the terminal speed of a sphere of silver (density =10.5 g/cm3) of the same size in the same liquid.

A ball of mass (m) 0.5 kg is attached to the end of a string having length (l) 0.5m. The ball is rotated on a horizontal circular path about vertical axis. The maximum tension that the string can bear is 324 N. The maximum possible value of angular velocity of ball (in rad/s) is

Water falls without splashing at a rate of 0.250 L/s from a height of 2.60 m into a 0.750 kg bucket on a scale. If the bucket is originally empty , what does the scale read 3 s after water starts to accumulate in it.

When two ends of a rod wrapped with cotton are maintained at different temperatures and after some time every point of the rod attains a constant temperature, then

Which of the following equipment is used to harness solar energy?

A steel wire fixed at both ends has a fundamentd: frequency of 200 Hz. A person can hear sound maximum frequency 14 kHz. What is the highest harmonic that can be played on this string which is audible to the person ?

The frequency of one of the lines in Paschen series of hydrogen atom is 2.340 ×1011 Hz. The quantum number n2 which produces this transition is:

If a line in the ZX-plane makes an angle 60o with Z-axis, the direction cosines of this line are:

The linear momentum of an electron revolving in the 2nd Bohr orbit is given by p=Kh where, h is the Planck's Constant. Predict the radius of the orbit.

Calculate the freezing point of a solution containing 60g of glucose (Molar mass = 180 g Mol−1) in 250 g of water. (kf of water=1.86 K kg mol−1)

A thief with a box of 25kg jumps from a tall building in the downward direction. What will be the weight of the box experienced by the the if during downward fall?. Justify

How many significant figures are there in 4200 kg?

Let ωH and ωE respectively be the angular speeds of the hour hand of a watch and that of the earth around its own axis. Compare the angular speeds of the earth and hour hand of a watch.

If the straight line y=mx+c passes through the points (3,-4) and (-1,2) then value of m is

What is the wavelength of a photon that has energy of 5.25 x 10-19J?

Assertion : Photoelectric effect demonstrates the wave nature of light. Reason : The number of photoelectrons is directly proportional to the frequency of light.

A dielectric slab of dielectric constant k=5 is placed between plates of parallel plate capacitor, thickness of slab is 30% of plate spacing &amp; its area is same as that of the plates, new capacitance is C′ &amp; old capacitance was C. The ratio C′C is approximately equal to

Figure 17.16 shows the P - V diagram for a fixed mass of an ideal gas undergoing cyclic process. AB represents isothermal process and CA represents adiabatic process. Which of the graphs shown in Fig. 17.17 represents the P - T diagram of the cyclic process ?

In magnetic field of electric current ,magnetic induction along the axis of long straight solenoid According to another circuit law $B.dl=u0 (nLI) Here current flowing through the rectangular path 'nl' times taken ,why

A dielectric slab of dielectric constant k=5 is placed between plates of parallel plate capacitor, thickness of slab is 30% of plate spacing & its area is same as that of the plates, new capacitance is C′ & old capacitance was C. The ratio C′C is approximately equal to