50278 + Interview Questions in Physics

1.	Two capillary tubes of same radius r but of lengths l1 and l2 are fitted in parallel to the bottom of a vessel. The pressure head is P. What should be the length of a single tube that can replace the two tubes so that the rate of flow is same as before
Answer» Two capillary tubes of same radius r but of lengths $l_{1}$ and $l_{2}$ are fitted in parallel to the bottom of a vessel. The pressure head is P. What should be the length of a single tube that can replace the two tubes so that the rate of flow is same as before

Discussion

2.	Two waves have equations x1=asin(ωt+ϕ1) and x2=asin(ωt+ϕ2). If in the resultant wave the frequency and amplitude remain equal to amplitude and frequency of each superimposing waves, the phase difference between them is
Answer» Two waves have equations $x_{1} = a sin (ω t + ϕ_{1})$ and $x_{2} = a sin (ω t + ϕ_{2})$ . If in the resultant wave the frequency and amplitude remain equal to amplitude and frequency of each superimposing waves, the phase difference between them is

Discussion

3.	In an ammeter, 10% of main current is passing through the galvanometer. If the resistance of the galvanometer is G, then the shunt resistance is
Answer» In an ammeter, $10 %$ of main current is passing through the galvanometer. If the resistance of the galvanometer is $G$ , then the shunt resistance is

Discussion

4.	When the load on a wire is slowly increased from 3 to 5 kg−wt, the elongation increases from 0.61 mm to 1.02 mm. The work done during the extension of wire is
Answer» When the load on a wire is slowly increased from 3 to 5 $k g - w t$ , the elongation increases from $0.61 m m$ to $1.02 m m$ . The work done during the extension of wire is

Discussion

5.	What is the melting point of tungsten? If it is very high then why the filament of the bulb is covered with glass to protect it from melting or burning?
Answer» What is the melting point of tungsten? If it is very high then why the filament of the bulb is covered with glass to protect it from melting or burning?

Discussion

6.	Why is the frictional force acting on the front tyre of a bicycle backwards?(while pedalling)
Answer» Why is the frictional force acting on the front tyre of a bicycle backwards?(while pedalling)

Discussion

7.	A particle of charge =1 μC and mass m = 1 gm starts moving from origin at t=0 under the electric field of 103 N/C along x-axis and magnetic field of 10 tesla along the same axis with the velocity of v=20^j m/s as shown, the speed of the particle at the time of 20√3 sec is n m/s. The value of n is m/s
Answer» A particle of charge $= 1$ $μ C$ and mass m = $1$ $g m$ starts moving from origin at $t = 0$ under the electric field of $10^{3} N / C$ along x-axis and magnetic field of $10$ $t e s l a$ along the same axis with the velocity of $v = 20^j$ $m / s$ as shown, the speed of the particle at the time of $20 \sqrt{3}$ $s e c$ is $n$ $m / s$ . The value of $n$ is $m / s$

Discussion

8.	Find the angle of deviation for the incident ray.
Answer» Find the angle of deviation for the incident ray.

Discussion

9.	The degree of the polynomial f(x,y)=3x2y−2√xy3+4xy−8x is
Answer» The degree of the polynomial $f (x, y) = 3 x^{2} y - 2 \sqrt{x} y^{3} + 4 x y - 8 x$ is

Discussion

10.	Two cars are travelling in the same direction with a velocity of 60 km per hour. they are separated by a distance of 5 km. a truck moving in opposite direction meets the two cars in a time interval of 3 minute. the velocity of the truck in kilometre per hour is ?
Answer» Two cars are travelling in the same direction with a velocity of 60 km per hour. they are separated by a distance of 5 km. a truck moving in opposite direction meets the two cars in a time interval of 3 minute. the velocity of the truck in kilometre per hour is ?

Discussion

11.	A body projected up reaches a point A in its path at the end of 4th second and reaches the ground after 5seconds from the start.The height of A above the ground is (g=9.8m/s)
Answer» A body projected up reaches a point A in its path at the end of 4th second and reaches the ground after 5seconds from the start.The height of A above the ground is (g=9.8m/s)

Discussion

12.	Magnetic field in the region is given by B = 2t T as shown in figure. Conducting rod of length L = 1 m starts moving with constant speed of v = 2 m/s at t = 0 and at x0=8 m. Time when current in resistor changes its direction is
Answer» Magnetic field in the region is given by B = 2t T as shown in figure. Conducting rod of length L = 1 m starts moving with constant speed of v = 2 m/s at t = 0 and at $x_{0} = 8 m$ . Time when current in resistor changes its direction is

Discussion

13.	A body is executing simple harmonic motion. At a displacement x, its potential energy is E1 and at a displacement y, its potential energy is E2. The potential energy E at a displacement (x+y) is (Assume that potential energy at mean position is zero)
Answer» A body is executing simple harmonic motion. At a displacement $x$ , its potential energy is $E_{1}$ and at a displacement $y$ , its potential energy is $E_{2}$ . The potential energy $E$ at a displacement $(x + y)$ is (Assume that potential energy at mean position is zero)

Discussion

14.	The point S is monochromatic source of light, emitting light of wavelength λ. At the point P at a distance x from the mirror as shown in the figure, interference takes place between two light rays one directly coming from source S and another after reflection from the mirror such that a maxima is formed. The value of x may be
Answer» The point $S$ is monochromatic source of light, emitting light of wavelength $λ$ . At the point $P$ at a distance $x$ from the mirror as shown in the figure, interference takes place between two light rays one directly coming from source $S$ and another after reflection from the mirror such that a maxima is formed. The value of $x$ may be

Discussion

15.	Which of the following statements about the CERN is/are correct? Codes :
Answer» Which of the following statements about the CERN is/are correct? Codes :

15.

Which of the following statements about the CERN is/are correct? Codes :

Answer»

Which of the following statements about the CERN is/are correct?

Codes :

Discussion

16.	A ceiling of a long hall is 25 m high what is the horizontal maximum distance that a ball thrown with speed of 40 m/s can go without hitting the ceiling of wall.
Answer» A ceiling of a long hall is 25 m high what is the horizontal maximum distance that a ball thrown with speed of 40 m/s can go without hitting the ceiling of wall.

Discussion

17.	One of the following is responsible for acute vision
Answer» One of the following is responsible for acute vision

Discussion

18.	Find the magnitude of →B, if →B makes an angle of 37∘ West of North and →C makes an angle of 45∘ North of East and →A has magnitude equal to 7√5 and →C has magnitude equal to 10√2. (Given →A+→B+→C=0)
Answer» Find the magnitude of $\to B$ , if $\to B$ makes an angle of $37^{\circ}$ West of North and $\to C$ makes an angle of $45^{\circ}$ North of East and $\to A$ has magnitude equal to $7 \sqrt{5}$ and $\to C$ has magnitude equal to $10 \sqrt{2}$ . (Given $\to A + \to B + \to C = 0$ )

Discussion

19.	Find the tension T1 in the string. Assume all surfaces to be smooth.
Answer» Find the tension $T_{1}$ in the string. Assume all surfaces to be smooth.

Discussion

20.	In the figure shown, find the ratio of tensions T1 and T2 assuming that the string and pulley is massless(correct up to 2 decimal places)
Answer» In the figure shown, find the ratio of tensions $T_{1}$ and $T_{2}$ assuming that the string and pulley is massless(correct up to 2 decimal places)

Discussion

21.	Five identical rods are joined as shown in figure. Point A and C are maintained at temperature 120∘C and 20∘C, respectively. The temperature of junction B will be
Answer» Five identical rods are joined as shown in figure. Point A and C are maintained at temperature $120^{\circ} C$ and $20^{\circ} C$ , respectively. The temperature of junction B will be

Discussion

22.	If the energy stored in spring 'A' is 20 J, then energy stored in spring 'B' is (under the same stretching force)
Answer» If the energy stored in spring ' $A$ ' is $20 J$ , then energy stored in spring ' $B$ ' is (under the same stretching force)

Discussion

23.	The distance of neptune and saturn from sun are nearly 1013 and 1012 meters respectively. Assuming that they move in circular orbits, their periodic times will be in the ratio
Answer» The distance of neptune and saturn from sun are nearly $10^{13}$ and $10^{12}$ meters respectively. Assuming that they move in circular orbits, their periodic times will be in the ratio

Discussion

24.	A litre of alcohol weighs
Answer» A litre of alcohol weighs

24.

A litre of alcohol weighs

Answer»

A litre of alcohol weighs

Discussion

25.	A force F=−K(yi+aj) (where K is a positive constant) acts on a particle moving in the xy-plane. Starting from the origin, the particle is taken along the positive x-axis to the point (a, 0) and then parallel to the y-axis to the point (a, a). The total work done by the force F on the particles is
Answer» A force $F = - K (y i + a j)$ (where K is a positive constant) acts on a particle moving in the xy-plane. Starting from the origin, the particle is taken along the positive x-axis to the point (a, 0) and then parallel to the y-axis to the point (a, a). The total work done by the force F on the particles is

Discussion

26.	A light ray travelling in glass medium is incident on glass-air interface at an angle of incidence θ. The reflected (R) and transmitted (T) intensities, both as function of θ, are plotted. The correct sketch is
Answer» A light ray travelling in glass medium is incident on glass-air interface at an angle of incidence $θ$ . The reflected (R) and transmitted (T) intensities, both as function of θ, are plotted. The correct sketch is

Discussion

27.	A spring is initially compressed by 2 m. Find out the work done required to compress another 6 m if spring constant k=2 N/m.
Answer» A spring is initially compressed by $2 m$ . Find out the work done required to compress another $6 m$ if spring constant $k = 2 N/m$ .

Discussion

28.	What's is Daniel cell,Galvanic cell and Voltaic cell? Are they all same or are different?
Answer» What's is Daniel cell,Galvanic cell and Voltaic cell? Are they all same or are different?

28.

What's is Daniel cell,Galvanic cell and Voltaic cell? Are they all same or are different?

Answer»

What's is Daniel cell,Galvanic cell and Voltaic cell?

Are they all same or are different?

Discussion

29.	For an isosceles prism of angle A and refractive index μ, it is found that the angle of minimum deviation δm=A. Which of the following option(s) is/are correct?
Answer» For an isosceles prism of angle $A$ and refractive index $μ$ , it is found that the angle of minimum deviation $δ_{m} = A$ . Which of the following option(s) is/are correct?

Discussion

30.	Two atoms are said to be bonded when:
Answer» Two atoms are said to be bonded when:

Discussion

31.	The maximum value of xy subject to x+y=4 is
Answer» The maximum value of $x y$ subject to $x + y = 4$ is

Discussion

32.	Evaluate sin(180∘−x).cot(270∘+x).tan(270∘−x).sec(180∘+x)
Answer» Evaluate $sin (180^{\circ} - x) . cot (270^{\circ} + x) . tan (270^{\circ} - x) . sec (180^{\circ} + x)$

Discussion

33.	The truth table for system of four NAND gates as shown in the figure is
Answer» The truth table for system of four NAND gates as shown in the figure is

Discussion

34.	A shell acquires the initial velocity v = 320 m/s, having made n = 2.0 turns inside the barrel whose length is equal to l = 2.0 m. Assuming that the shell moves inside the barrel with a uniform acceleration, find the angular velocity of its axial rotation, at the moment when the shell escapes the barrel.
Answer» A shell acquires the initial velocity $v$ = 320 m/s, having made $n$ = 2.0 turns inside the barrel whose length is equal to $l$ = 2.0 m. Assuming that the shell moves inside the barrel with a uniform acceleration, find the angular velocity of its axial rotation, at the moment when the shell escapes the barrel.

Discussion

35.	The number of selection of n objects from 2n objects of which n are identical and the rest are different is
Answer» The number of selection of $n$ objects from $2 n$ objects of which $n$ are identical and the rest are different is

Discussion

36.	A rigid body is one
Answer» A rigid body is one

Discussion

37.	A bullet of mass 20 g moving horizontally at a speed of 300 m/s is fired into a wooden block of mass 500 g suspended by a long string.The bullet crosses the block and emerges on the other side.If the centre of mass of the block rises through a height of 20.0 cm,find the speed of the bullet as it emerges from the block.
Answer» A bullet of mass 20 g moving horizontally at a speed of 300 m/s is fired into a wooden block of mass 500 g suspended by a long string.The bullet crosses the block and emerges on the other side.If the centre of mass of the block rises through a height of 20.0 cm,find the speed of the bullet as it emerges from the block.

Discussion

38.	A change in a vector may occur due to rotation of the vector. Explain.
Answer» A change in a vector may occur due to rotation of the vector. Explain.

Discussion

39.	Self inductance of unit length of two co-axial cylinders, the inner one of radius a and outer one of radius b, carrying same current but in opposite direction is
Answer» Self inductance of unit length of two co-axial cylinders, the inner one of radius a and outer one of radius b, carrying same current but in opposite direction is

Discussion

40.	Two stones of masses m and 2m are whirled in horizontal circles. The heavier one is whirled in a circle of radius r2 and the lighter one in a circle of radius r. The tangential speed of lighter stone is n times that of the speed of heavier stone. If they experience the same centripetal forces, the value of n is
Answer» Two stones of masses $m$ and $2 m$ are whirled in horizontal circles. The heavier one is whirled in a circle of radius $\frac{r}{2}$ and the lighter one in a circle of radius $r$ . The tangential speed of lighter stone is $n$ times that of the speed of heavier stone. If they experience the same centripetal forces, the value of $n$ is

Discussion

41.	The US athlete Florence Griffith - Joyner won the 100 m sprint gold medal at SeoulOlympic 1988 setting a new Olympic record of 10.54 s. Assume that she achieved her maximum speed in a very short-time and then ran the race with that speed till she crossed the line. Take her mass to be 50 kg. Assuming that the track, the wind etc. offered an average resistance of one tenth of her weight, calculate the work done by the resistance during the run.
Answer» The US athlete Florence Griffith - Joyner won the 100 m sprint gold medal at SeoulOlympic 1988 setting a new Olympic record of 10.54 s. Assume that she achieved her maximum speed in a very short-time and then ran the race with that speed till she crossed the line. Take her mass to be 50 kg. Assuming that the track, the wind etc. offered an average resistance of one tenth of her weight, calculate the work done by the resistance during the run.

Discussion

42.	A block of mass 50 kg can slide on a rough horizontal surface. The coefficient of friction between the block and the surface is 0.6. The least force of pull acting at an angle of 30∘ from the horizontal which causes the block to just slide is
Answer» A block of mass $50 k g$ can slide on a rough horizontal surface. The coefficient of friction between the block and the surface is $0.6$ . The least force of pull acting at an angle of $30^{\circ}$ from the horizontal which causes the block to just slide is

Discussion

43.	Find the time constant of charging of the circuit as shown in the figure.
Answer» Find the time constant of charging of the circuit as shown in the figure.

Discussion

44.	Two identical pith balls, each carrying a charge q, are suspended from a common point by two strings of equal length l. Find the mass of each ball if the angle between the strings is 2θ in equilibrium.
Answer» Two identical pith balls, each carrying a charge q, are suspended from a common point by two strings of equal length l. Find the mass of each ball if the angle between the strings is $2 θ$ in equilibrium.

Discussion

45.	The transition from the state n = 4 to n = 3 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from :
Answer» The transition from the state n = 4 to n = 3 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from :

Discussion

46.	Consider the situation shown in figure (32-E36). The switch is closed at t = 0 when the capacitors are uncharged. Find the charge on the capacitor C1 as a function of time t.
Answer» Consider the situation shown in figure (32-E36). The switch is closed at t = 0 when the capacitors are uncharged. Find the charge on the capacitor $C_{1}$ as a function of time t.

46.

Consider the situation shown in figure (32-E36). The switch is closed at t = 0 when the capacitors are uncharged. Find the charge on the capacitor C1 as a function of time t.

Answer»

Consider the situation shown in figure (32-E36). The switch is closed at t = 0 when the capacitors are uncharged. Find the charge on the capacitor $C_{1}$ as a function of time t.

Discussion

47.	A cyclic process ABCA is shown in the V-T diagram. Process on the P-V diagram is
Answer» A cyclic process ABCA is shown in the V-T diagram. Process on the P-V diagram is

Discussion

48.	The pressure of air in a soap bubble of 0.7cm diameter is 8 mm of water above the pressure outside. The surface tension of the soap solution is
Answer» The pressure of air in a soap bubble of 0.7cm diameter is 8 mm of water above the pressure outside. The surface tension of the soap solution is

Discussion

49.	A violin player riding on a slow train plays a 440 Hz note. Another violin player standing near the track plays the same note. When the two are close by and the train approaches the person on the ground, he hears 4.0 beats per second. The speed of sound in air = 340 m/s. (a) Calculate the speed of the train. (b) What beat frequency is heard by the player in the train ?
Answer» A violin player riding on a slow train plays a 440 Hz note. Another violin player standing near the track plays the same note. When the two are close by and the train approaches the person on the ground, he hears 4.0 beats per second. The speed of sound in air = 340 m/s. (a) Calculate the speed of the train. (b) What beat frequency is heard by the player in the train ?

Discussion

50.	A perfect gas at 27∘C is heated at constant pressure to 327∘C. If original volume of gas at 27∘C is V then volume at 327∘C is
Answer» A perfect gas at $27^{\circ} C$ is heated at constant pressure to $327^{\circ} C$ . If original volume of gas at $27^{\circ} C$ is V then volume at $327^{\circ} C$ is

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Two capillary tubes of same radius r but of lengths l1 and l2 are fitted in parallel to the bottom of a vessel. The pressure head is P. What should be the length of a single tube that can replace the two tubes so that the rate of flow is same as before

Two waves have equations x1=asin(ωt+ϕ1) and x2=asin(ωt+ϕ2). If in the resultant wave the frequency and amplitude remain equal to amplitude and frequency of each superimposing waves, the phase difference between them is

In an ammeter, 10% of main current is passing through the galvanometer. If the resistance of the galvanometer is G, then the shunt resistance is

When the load on a wire is slowly increased from 3 to 5 kg−wt, the elongation increases from 0.61 mm to 1.02 mm. The work done during the extension of wire is

What is the melting point of tungsten? If it is very high then why the filament of the bulb is covered with glass to protect it from melting or burning?

Why is the frictional force acting on the front tyre of a bicycle backwards?(while pedalling)

Find the angle of deviation for the incident ray.

The degree of the polynomial f(x,y)=3x2y−2√xy3+4xy−8x is

Two cars are travelling in the same direction with a velocity of 60 km per hour. they are separated by a distance of 5 km. a truck moving in opposite direction meets the two cars in a time interval of 3 minute. the velocity of the truck in kilometre per hour is ?

A body projected up reaches a point A in its path at the end of 4th second and reaches the ground after 5seconds from the start.The height of A above the ground is (g=9.8m/s)

Magnetic field in the region is given by B = 2t T as shown in figure. Conducting rod of length L = 1 m starts moving with constant speed of v = 2 m/s at t = 0 and at x0=8 m. Time when current in resistor changes its direction is

A body is executing simple harmonic motion. At a displacement x, its potential energy is E1 and at a displacement y, its potential energy is E2. The potential energy E at a displacement (x+y) is (Assume that potential energy at mean position is zero)

Which of the following statements about the CERN is/are correct? Codes :

A ceiling of a long hall is 25 m high what is the horizontal maximum distance that a ball thrown with speed of 40 m/s can go without hitting the ceiling of wall.

One of the following is responsible for acute vision

Find the magnitude of →B, if →B makes an angle of 37∘ West of North and →C makes an angle of 45∘ North of East and →A has magnitude equal to 7√5 and →C has magnitude equal to 10√2. (Given →A+→B+→C=0)

Find the tension T1 in the string. Assume all surfaces to be smooth.

In the figure shown, find the ratio of tensions T1 and T2 assuming that the string and pulley is massless(correct up to 2 decimal places)

Five identical rods are joined as shown in figure. Point A and C are maintained at temperature 120∘C and 20∘C, respectively. The temperature of junction B will be

If the energy stored in spring 'A' is 20 J, then energy stored in spring 'B' is (under the same stretching force)

The distance of neptune and saturn from sun are nearly 1013 and 1012 meters respectively. Assuming that they move in circular orbits, their periodic times will be in the ratio

A litre of alcohol weighs

A force F=−K(yi+aj) (where K is a positive constant) acts on a particle moving in the xy-plane. Starting from the origin, the particle is taken along the positive x-axis to the point (a, 0) and then parallel to the y-axis to the point (a, a). The total work done by the force F on the particles is

A light ray travelling in glass medium is incident on glass-air interface at an angle of incidence θ. The reflected (R) and transmitted (T) intensities, both as function of θ, are plotted. The correct sketch is

A spring is initially compressed by 2 m. Find out the work done required to compress another 6 m if spring constant k=2 N/m.

What's is Daniel cell,Galvanic cell and Voltaic cell? Are they all same or are different?

For an isosceles prism of angle A and refractive index μ, it is found that the angle of minimum deviation δm=A. Which of the following option(s) is/are correct?

Two atoms are said to be bonded when:

The maximum value of xy subject to x+y=4 is

Evaluate sin(180∘−x).cot(270∘+x).tan(270∘−x).sec(180∘+x)

The truth table for system of four NAND gates as shown in the figure is

The number of selection of n objects from 2n objects of which n are identical and the rest are different is

A rigid body is one

A change in a vector may occur due to rotation of the vector. Explain.

Self inductance of unit length of two co-axial cylinders, the inner one of radius a and outer one of radius b, carrying same current but in opposite direction is

A block of mass 50 kg can slide on a rough horizontal surface. The coefficient of friction between the block and the surface is 0.6. The least force of pull acting at an angle of 30∘ from the horizontal which causes the block to just slide is

Find the time constant of charging of the circuit as shown in the figure.

Two identical pith balls, each carrying a charge q, are suspended from a common point by two strings of equal length l. Find the mass of each ball if the angle between the strings is 2θ in equilibrium.

The transition from the state n = 4 to n = 3 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from :

Consider the situation shown in figure (32-E36). The switch is closed at t = 0 when the capacitors are uncharged. Find the charge on the capacitor C1 as a function of time t.

A cyclic process ABCA is shown in the V-T diagram. Process on the P-V diagram is

The pressure of air in a soap bubble of 0.7cm diameter is 8 mm of water above the pressure outside. The surface tension of the soap solution is

A perfect gas at 27∘C is heated at constant pressure to 327∘C. If original volume of gas at 27∘C is V then volume at 327∘C is