50278 + Interview Questions in Physics

1.	A particle executes SHM in a line 4 cm long. Its velocity when passing through the centre of line is 12 cm/s. The period will be
Answer» A particle executes SHM in a line 4 cm long. Its velocity when passing through the centre of line is 12 cm/s. The period will be

1.

A particle executes SHM in a line 4 cm long. Its velocity when passing through the centre of line is 12 cm/s. The period will be

Answer»

A particle executes SHM in a line 4 cm long. Its velocity when passing through the centre of line is 12 cm/s. The period will be

Discussion

2.	Figure shows an incident pulse P reflected from a rigid support. Which one of the following options represent the reflected pulse?
Answer» Figure shows an incident pulse $P$ reflected from a rigid support. Which one of the following options represent the reflected pulse?

Discussion

3.	A boy walks uniformally along the sides of a rectangular park of size 400 m× 300 m, starting from one corner to the other corner diagonally opposite. Which of the following statement is incorrect
Answer» A boy walks uniformally along the sides of a rectangular park of size 400 m× 300 m, starting from one corner to the other corner diagonally opposite. Which of the following statement is incorrect

Discussion

4.	A square loop ABCD, carrying a current i, is placed near and coplanar with a long straight conductor XY carrying a current I, the net force on the loop will be
Answer» A square loop ABCD, carrying a current $i$ , is placed near and coplanar with a long straight conductor XY carrying a current $I$ , the net force on the loop will be

Discussion

5.	An electric field is acting vertically upwards. A small body of mass 1 gm and charge –1μC is projected with a velocity 10 m/s at an angle 45∘ with horizontal. Its horizontal range is 2m then the intensity of electric field is: (g = 10 m/s2)
Answer» An electric field is acting vertically upwards. A small body of mass 1 gm and charge –1 $μ C$ is projected with a velocity 10 m/s at an angle $45^{\circ}$ with horizontal. Its horizontal range is 2m then the intensity of electric field is: (g = 10 $m / s^{2}$ )

Discussion

6.	The energy levels of a certain atom for 1st, 2nd and 3rd levels are E, 4E3 and 2E respectively. A photon of wavelength λ is emitted for a transition 3→1. What will be the wavelength of emissions for transition 2→1
Answer» The energy levels of a certain atom for 1st, 2nd and 3rd levels are E, $\frac{4 E}{3}$ and 2E respectively. A photon of wavelength $λ$ is emitted for a transition $3 \to 1$ . What will be the wavelength of emissions for transition $2 \to 1$

Discussion

7.	If in the given figure i = 0.25 amp, then the value R will be
Answer» If in the given figure i = 0.25 amp, then the value R will be

Discussion

8.	0.216g of an organic compound gave 28.8cm3 of moist nitrogen measured at 288k and 732.7 mm pressure. The percentage of N2 in the substance is approximately (aqueous tension is 12.7mm)
Answer» 0.216g of an organic compound gave $28.8 c m ^{3}$ of moist nitrogen measured at 288k and 732.7 mm pressure. The percentage of $N_{} 2$ in the substance is approximately (aqueous tension is 12.7mm)

Discussion

9.	Photo cell is a device to
Answer» Photo cell is a device to

Discussion

10.	Quantam nature of light is explained by which of the following phenomenon
Answer» Quantam nature of light is explained by which of the following phenomenon

Discussion

11.	A tank used for filling helium balloons has a volume of 0.3 m3 and contains 2 mol of helium gas at 20∘C. Assuming that the helium behaves like an ideal gas, find the total translational kinetic energy of the molecules of the gas
Answer» A tank used for filling helium balloons has a volume of $0.3 m^{3}$ and contains $2 mol$ of helium gas at $20^{\circ} C$ . Assuming that the helium behaves like an ideal gas, find the total translational kinetic energy of the molecules of the gas

Discussion

12.	Match the following 1. Sound waves (i) Mechanical wave 2. Light waves (ii) Non-mechanical waves 3. Waves on a string (iii) Transverse waves (iv) Longitudinal waves
Answer» Match the following 1. Sound waves (i) Mechanical wave 2. Light waves (ii) Non-mechanical waves 3. Waves on a string (iii) Transverse waves (iv) Longitudinal waves

12.

Match the following 1. Sound waves (i) Mechanical wave 2. Light waves (ii) Non-mechanical waves 3. Waves on a string (iii) Transverse waves (iv) Longitudinal waves

Answer»

Match the following

1. Sound waves (i) Mechanical wave

2. Light waves (ii) Non-mechanical waves

3. Waves on a string (iii) Transverse waves

(iv) Longitudinal waves

Discussion

13.	Given →A+→B=→Cand the magnitudes of vectors →A, →B and →C are respectively 12, 5 and 13 units. The angle between →A and →B is
Answer» Given $\to A + \to B = \to C$ and the magnitudes of vectors $\to A$ , $\to B$ and $\to C$ are respectively 12, 5 and 13 units. The angle between $\to A$ and $\to B$ is

Discussion

14.	The dimensions of 1/μ0ε0. where symbols have their usual meanings, are
Answer» The dimensions of $1 / μ_{0} ε_{0}$ . where symbols have their usual meanings, are

Discussion

15.	Which of the following radiations has the least wavelength?
Answer» Which of the following radiations has the least wavelength?

Discussion

16.	A body of mass 2 kg moving on a horizontal surface with an initial velocity of 4 m/sec comes to rest after 2 sec. If one wants to keep this body moving on the same surface with a velocity of 4 m/sec, the force required is
Answer» A body of mass 2 kg moving on a horizontal surface with an initial velocity of 4 m/sec comes to rest after 2 sec. If one wants to keep this body moving on the same surface with a velocity of 4 m/sec, the force required is

Discussion

17.	For a CE-transistor amplifier, the audio signal voltage across the collector resistance of 2 kΩ is 2 V. Suppose the current amplification factor of the transistor is 100, find the input signal voltage and base current, if the base resistance is 1 kΩ.
Answer» For a CE-transistor amplifier, the audio signal voltage across the collector resistance of 2 k $Ω$ is 2 V. Suppose the current amplification factor of the transistor is 100, find the input signal voltage and base current, if the base resistance is 1 k $Ω$ .

Discussion

18.	Why do the electrostatic field lines not form closed loops?
Answer» Why do the electrostatic field lines not form closed loops?

Discussion

19.	(i) Explain with the help of a diagram, the formation of depletion region and barrier potential in a p-n junction. (ii) Draw the circuit diagram of a half wave rectifier and explain its working.
Answer» (i) Explain with the help of a diagram, the formation of depletion region and barrier potential in a p-n junction. (ii) Draw the circuit diagram of a half wave rectifier and explain its working.

Discussion

20.	The rms velocity at NTP of the species can be calculated from the expression
Answer» The rms velocity at NTP of the species can be calculated from the expression

20.

The rms velocity at NTP of the species can be calculated from the expression

Answer»

The rms velocity at NTP of the species can be calculated from the expression

Discussion

21.	A FM channel RADIO BYJUS operates at a frequency 100 MHz, then the wavelength of signals is (speed of sound wave =330 m/s, speed of EM wave =3×108 m/s)
Answer» A FM channel RADIO BYJUS operates at a frequency $100 MHz$ , then the wavelength of signals is (speed of sound wave $= 330 m/s$ , speed of EM wave $= 3 \times 10^{8} m/s$ )

Discussion

22.	The introduction of a metal plate between the plates of a parallel plate capacitor increases its capacitance by 4.5 times. If d is the separation of the two plates of the capacitor, the thickness of the metal plate introduced is
Answer» The introduction of a metal plate between the plates of a parallel plate capacitor increases its capacitance by 4.5 times. If d is the separation of the two plates of the capacitor, the thickness of the metal plate introduced is

Discussion

23.	Two points A and B are at a distance a and b respectively from an infinite metal plate having charge density as ‘σ’ C m−2. Potential difference between A and B is
Answer» Two points A and B are at a distance a and b respectively from an infinite metal plate having charge density as ‘ $σ$ ’ C $m^{- 2}$ . Potential difference between A and B is

Discussion

24.	The reading of the ammeter in the circuit in Fig. is,
Answer» The reading of the ammeter in the circuit in Fig. is,

24.

The reading of the ammeter in the circuit in Fig. is,

Answer»

The reading of the ammeter in the circuit in Fig. is,

Discussion

25.	Three charges each of magnitude q are placed at vertices of an equilateral triangle. A fourth charge -Q is placed at centroid of triangle so that system of 4 charges remains in equilibrium. Magnitude of charge Q is such that q = nQ, where n is (Answer upto two decimal places)
Answer» Three charges each of magnitude q are placed at vertices of an equilateral triangle. A fourth charge -Q is placed at centroid of triangle so that system of 4 charges remains in equilibrium. Magnitude of charge Q is such that q = nQ, where n is (Answer upto two decimal places)

Discussion

26.	A cord is wrapped around a pulley that is shaped like a disk of mass m and radius r. The cord's free end is connected to a block of mass M. The block starts from rest and then slides down an incline that makes an angle θ with the horizontal as shown in figure. The coefficient of kinetic friction between block and incline is μ . Then the magnitude of the acceleration of the block is
Answer» A cord is wrapped around a pulley that is shaped like a disk of mass $m$ and radius $r$ . The cord's free end is connected to a block of mass $M$ . The block starts from rest and then slides down an incline that makes an angle $θ$ with the horizontal as shown in figure. The coefficient of kinetic friction between block and incline is $μ$ . Then the magnitude of the acceleration of the block is

Discussion

27.	An aeroplane is rising vertically with acceleration f. Two stones are dropped from it at an interval of time t. The distance between them at time t′ after the second stone is dropped will be
Answer» An aeroplane is rising vertically with acceleration $f$ . Two stones are dropped from it at an interval of time $t$ . The distance between them at time $t^{'}$ after the second stone is dropped will be

Discussion

28.	Moment of inertia of a body about a given axis is 1.5 kg-m2. Initially the body is at rest. In order to produce a rotational kinetic energy of 1200 J, the angular acceleration of 20 rad/s2 must be applied about the axis for a duration of
Answer» Moment of inertia of a body about a given axis is $1.5 {kg-m}^{2}$ . Initially the body is at rest. In order to produce a rotational kinetic energy of $1200 J$ , the angular acceleration of $20 {rad/s}^{2}$ must be applied about the axis for a duration of

Discussion

29.	Minute hand of a watch is 4 cm long. How far does it's tip moves in 45 minutes? (use π=3.14)
Answer» Minute hand of a watch is $4 cm$ long. How far does it's tip moves in $45 minutes$ ? (use $π = 3.14$ )

Discussion

30.	The elastic limit of steel is 8×108Nm−2 and its Young modulus 2×1011Nm−2. Find the maximum elongation of a half-metre steel wire that can be given without exceeding the elastic limit.
Answer» The elastic limit of steel is $8 \times 10^{8} N m^{- 2}$ and its Young modulus $2 \times 10^{11} N m^{- 2}$ . Find the maximum elongation of a half-metre steel wire that can be given without exceeding the elastic limit.

30.

The elastic limit of steel is 8×108Nm−2 and its Young modulus 2×1011Nm−2. Find the maximum elongation of a half-metre steel wire that can be given without exceeding the elastic limit.

Answer»

The elastic limit of steel is $8 \times 10^{8} N m^{- 2}$ and its Young modulus $2 \times 10^{11} N m^{- 2}$ . Find the maximum elongation of a half-metre steel wire that can be given without exceeding the elastic limit.

Discussion

31.	A point mass m is attached at the end of a massless rod of length L. Other end of rod is hinged to frictionless hinge. Sudden velocity V=√9gL2 is provided to the point mass as shown in figure. So hinge reaction when this rod rotates by 1800 is
Answer» A point mass m is attached at the end of a massless rod of length L. Other end of rod is hinged to frictionless hinge. Sudden velocity $V = \sqrt{\frac{9 g L}{2}}$ is provided to the point mass as shown in figure. So hinge reaction when this rod rotates by $180^{0}$ is

Discussion

32.	The circuit shown in the figure contains two diodes D1 and D2 each with a forward resistance of 50 ohms and with infinite backward resistance. If the battery voltage is 6V, the current through the 100 ohm resistance (in Amperes) is:
Answer» The circuit shown in the figure contains two diodes $D_{1}$ and $D_{2}$ each with a forward resistance of 50 ohms and with infinite backward resistance. If the battery voltage is 6V, the current through the 100 ohm resistance (in Amperes) is:

32.

The circuit shown in the figure contains two diodes D1 and D2 each with a forward resistance of 50 ohms and with infinite backward resistance. If the battery voltage is 6V, the current through the 100 ohm resistance (in Amperes) is:

Answer»

The circuit shown in the figure contains two diodes $D_{1}$ and $D_{2}$ each with a forward resistance of 50 ohms and with infinite backward resistance. If the battery voltage is 6V, the current through the 100 ohm resistance (in Amperes) is:

Discussion

33.	In the figure shown a current I1 is established in the long straight wire AB. Another wire CD carrying current I2 is placed in the plane of the paper. The line joining the ends of this wire is perpendicular to the wire AB. The resultant force on the wire CD is:
Answer» In the figure shown a current I₁ is established in the long straight wire AB. Another wire CD carrying current I₂ is placed in the plane of the paper. The line joining the ends of this wire is perpendicular to the wire AB. The resultant force on the wire CD is:

33.

In the figure shown a current I1 is established in the long straight wire AB. Another wire CD carrying current I2 is placed in the plane of the paper. The line joining the ends of this wire is perpendicular to the wire AB. The resultant force on the wire CD is:

Answer»

In the figure shown a current I₁ is established in the long straight wire AB. Another wire CD carrying current I₂ is placed in the plane of the paper. The line joining the ends of this wire is perpendicular to the wire AB. The resultant force on the wire CD is:

Discussion

34.	The work done to move 25×1018 electrons between two points is 100 mJ. What is the potential difference between the two points?
Answer» The work done to move $25 \times 10^{18}$ electrons between two points is 100 mJ. What is the potential difference between the two points?

Discussion

35.	Two rods of different materials are kept in series. If temperature of the junction is 30∘C, find K1K2
Answer» Two rods of different materials are kept in series. If temperature of the junction is $30^{\circ} C$ , find $\frac{K_{1}}{K_{2}}$

Discussion

36.	An object is placed 15 cm in front of a convex lens of focal length 10 cm. Find the nature and position of the image formed. Where should a concave mirror of radius of curvature 20 cm be placed so that the final image is formed at the position of the object itself?
Answer» An object is placed 15 cm in front of a convex lens of focal length 10 cm. Find the nature and position of the image formed. Where should a concave mirror of radius of curvature 20 cm be placed so that the final image is formed at the position of the object itself?

Discussion

37.	The moment of inertia of a uniform cylinder of length l and radius R about its perpendicular bisector is I. What is the ratio l/R such that the moment of inertia is minimum ?
Answer» The moment of inertia of a uniform cylinder of length $l$ and radius $R$ about its perpendicular bisector is $I$ . What is the ratio $l / R$ such that the moment of inertia is minimum ?

Discussion

38.	Two identical blocks P and Q have mass ‘m’ each. They are attached to two identical springs initially unstretched. Now the left spring (along with P) is compressed by A2 and the right spring (along with Q) is compressed by A. Both the blocks are released simultaneously. They collide perfectly inelastically. Initial time period of both the blocks was T. [consider K as spring constant of each spring] The energy of oscillation of the combined mass is
Answer» Two identical blocks P and Q have mass ‘m’ each. They are attached to two identical springs initially unstretched. Now the left spring (along with P) is compressed by $\frac{A}{2}$ and the right spring (along with Q) is compressed by A. Both the blocks are released simultaneously. They collide perfectly inelastically. Initial time period of both the blocks was T. [consider K as spring constant of each spring] The energy of oscillation of the combined mass is

38.

Two identical blocks P and Q have mass ‘m’ each. They are attached to two identical springs initially unstretched. Now the left spring (along with P) is compressed by A2 and the right spring (along with Q) is compressed by A. Both the blocks are released simultaneously. They collide perfectly inelastically. Initial time period of both the blocks was T. [consider K as spring constant of each spring] The energy of oscillation of the combined mass is

Answer»

Two identical blocks P and Q have mass ‘m’ each. They are attached to two identical springs initially unstretched. Now the left spring (along with P) is compressed by $\frac{A}{2}$ and the right spring (along with Q) is compressed by A. Both the blocks are released simultaneously. They collide perfectly inelastically. Initial time period of both the blocks was T. [consider K as spring constant of each spring]

The energy of oscillation of the combined mass is

Discussion

39.	An insulating sphere of radius R having a cavity of radius R4 at the periphery is charged uniformly with charge Q. If the magnitude of electric field at point 'P' due to the above charge distribution is 8αKQ63R2, then the value of α is (Answer upto two digits after the decimal point)
Answer» An insulating sphere of radius $R$ having a cavity of radius $\frac{R}{4}$ at the periphery is charged uniformly with charge $Q$ . If the magnitude of electric field at point 'P' due to the above charge distribution is $\frac{8 α K Q}{63 R^{2}}$ , then the value of $α$ is (Answer upto two digits after the decimal point)

Discussion

40.	A rocket has a mass of 1000 kg with 50,000 kg of fuel being stored on this rocket. The nozzle of the rocket lets out the exhaust gases at a speed of 500 m/s. If the rocket consumes fuel at the rate of 100 kg/s, what is the acceleration of the rocket after 5 minutes in a gravity free space?
Answer» A rocket has a mass of $1000 kg$ with $50, 000 kg$ of fuel being stored on this rocket. The nozzle of the rocket lets out the exhaust gases at a speed of $500 m/s$ . If the rocket consumes fuel at the rate of $100 kg/s$ , what is the acceleration of the rocket after $5 minutes$ in a gravity free space?

Discussion

41.	Two conductors having same width and length, thickness d1 and d2, thermal conductivity K1 and K2 are placed one above the another. Find the equivalent thermal conductivity parallel to the contact surface such that the temperature difference across both the faces of both the conductors are same.
Answer» Two conductors having same width and length, thickness $d_{1}$ and $d_{2}$ , thermal conductivity $K_{1}$ and $K_{2}$ are placed one above the another. Find the equivalent thermal conductivity parallel to the contact surface such that the temperature difference across both the faces of both the conductors are same.

Discussion

42.	How much work should be done in decreasing the volume of an ideal gas by an amount of 2.4×10−4 m3 at normal temperature and constant pressure of 1×105 N/m2 ?
Answer» How much work should be done in decreasing the volume of an ideal gas by an amount of $2.4 \times 10^{- 4} m^{3}$ at normal temperature and constant pressure of $1 \times 10^{5} {N/m}^{2}$ ?

Discussion

43.	Can energy be zero in E=mc2 equation? Give reason.
Answer» Can energy be zero in $E = m c^{2}$ equation? Give reason.

Discussion

44.	A wire suspended vertically from one end of its ends is stretched by attaching a weight of 200 N to the lower end. The weight stretches the wire by 1 mm. Then the elastic energy stored in the wire(in J) is
Answer» A wire suspended vertically from one end of its ends is stretched by attaching a weight of $200 N$ to the lower end. The weight stretches the wire by $1 mm$ . Then the elastic energy stored in the wire(in J) is

Discussion

45.	A football player kicked a ball with a velocity of 20 ms−1 in a direction making an angle of 60∘ with horizontal. Find the velocity with which he should run in the same direction so that the ball remains above this head.
Answer» A football player kicked a ball with a velocity of $20 {ms}^{- 1}$ in a direction making an angle of $60^{\circ}$ with horizontal. Find the velocity with which he should run in the same direction so that the ball remains above this head.

Discussion

46.	A body of mass 6 kg user under a force which causes displacement in it given S=t^2/4 meters where t is time . The work done by the force in 2 sec is..?
Answer» A body of mass 6 kg user under a force which causes displacement in it given S=t^2/4 meters where t is time . The work done by the force in 2 sec is..?

Discussion

47.	A block of 2 kg is suspended from the ceiling through a massless spring of spring constant k = 100 N/m. What is the elongation of the spring ? If another 1 kg is added to the block, what would be the further elongation ?
Answer» A block of 2 kg is suspended from the ceiling through a massless spring of spring constant k = 100 N/m. What is the elongation of the spring ? If another 1 kg is added to the block, what would be the further elongation ?

Discussion

48.	The kinetic energy of a projectile at the highest point of it projection is 75% of its kinetic energy at the point of projection. Find the angle of projection.
Answer» The kinetic energy of a projectile at the highest point of it projection is $75$ % of its kinetic energy at the point of projection. Find the angle of projection.

Discussion

49.	In electric flux taken in sphere the electric field and area are taken in same direction when a q positive charge is taken at centre the angle between electric field and the area is 0 then dot product of their will zero or not
Answer» In electric flux taken in sphere the electric field and area are taken in same direction when a q positive charge is taken at centre the angle between electric field and the area is 0 then dot product of their will zero or not

Discussion

50.	A fireman of mass 80 kg slides down a pole during a rescue mission. The force of friction is constant at 720 N. Find the acceleration of the man.
Answer» A fireman of mass 80 kg slides down a pole during a rescue mission. The force of friction is constant at 720 N. Find the acceleration of the man.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A particle executes SHM in a line 4 cm long. Its velocity when passing through the centre of line is 12 cm/s. The period will be

Figure shows an incident pulse P reflected from a rigid support. Which one of the following options represent the reflected pulse?

A boy walks uniformally along the sides of a rectangular park of size 400 m× 300 m, starting from one corner to the other corner diagonally opposite. Which of the following statement is incorrect

A square loop ABCD, carrying a current i, is placed near and coplanar with a long straight conductor XY carrying a current I, the net force on the loop will be

An electric field is acting vertically upwards. A small body of mass 1 gm and charge –1μC is projected with a velocity 10 m/s at an angle 45∘ with horizontal. Its horizontal range is 2m then the intensity of electric field is: (g = 10 m/s2)

The energy levels of a certain atom for 1st, 2nd and 3rd levels are E, 4E3 and 2E respectively. A photon of wavelength λ is emitted for a transition 3→1. What will be the wavelength of emissions for transition 2→1

If in the given figure i = 0.25 amp, then the value R will be

0.216g of an organic compound gave 28.8cm­3 of moist nitrogen measured at 288k and 732.7 mm pressure. The percentage of N­2 in the substance is approximately (aqueous tension is 12.7mm)

Photo cell is a device to

Quantam nature of light is explained by which of the following phenomenon

A tank used for filling helium balloons has a volume of 0.3 m3 and contains 2 mol of helium gas at 20∘C. Assuming that the helium behaves like an ideal gas, find the total translational kinetic energy of the molecules of the gas

Match the following 1. Sound waves (i) Mechanical wave 2. Light waves (ii) Non-mechanical waves 3. Waves on a string (iii) Transverse waves (iv) Longitudinal waves

Given →A+→B=→Cand the magnitudes of vectors →A, →B and →C are respectively 12, 5 and 13 units. The angle between →A and →B is

The dimensions of 1/μ0ε0. where symbols have their usual meanings, are

Which of the following radiations has the least wavelength?

A body of mass 2 kg moving on a horizontal surface with an initial velocity of 4 m/sec comes to rest after 2 sec. If one wants to keep this body moving on the same surface with a velocity of 4 m/sec, the force required is

For a CE-transistor amplifier, the audio signal voltage across the collector resistance of 2 kΩ is 2 V. Suppose the current amplification factor of the transistor is 100, find the input signal voltage and base current, if the base resistance is 1 kΩ.

Why do the electrostatic field lines not form closed loops?

(i) Explain with the help of a diagram, the formation of depletion region and barrier potential in a p-n junction. (ii) Draw the circuit diagram of a half wave rectifier and explain its working.

The rms velocity at NTP of the species can be calculated from the expression

A FM channel RADIO BYJUS operates at a frequency 100 MHz, then the wavelength of signals is (speed of sound wave =330 m/s, speed of EM wave =3×108 m/s)

The introduction of a metal plate between the plates of a parallel plate capacitor increases its capacitance by 4.5 times. If d is the separation of the two plates of the capacitor, the thickness of the metal plate introduced is

Two points A and B are at a distance a and b respectively from an infinite metal plate having charge density as ‘σ’ C m−2. Potential difference between A and B is

The reading of the ammeter in the circuit in Fig. is,

Three charges each of magnitude q are placed at vertices of an equilateral triangle. A fourth charge -Q is placed at centroid of triangle so that system of 4 charges remains in equilibrium. Magnitude of charge Q is such that q = nQ, where n is (Answer upto two decimal places)

An aeroplane is rising vertically with acceleration f. Two stones are dropped from it at an interval of time t. The distance between them at time t′ after the second stone is dropped will be

Moment of inertia of a body about a given axis is 1.5 kg-m2. Initially the body is at rest. In order to produce a rotational kinetic energy of 1200 J, the angular acceleration of 20 rad/s2 must be applied about the axis for a duration of

Minute hand of a watch is 4 cm long. How far does it's tip moves in 45 minutes? (use π=3.14)

The elastic limit of steel is 8×108Nm−2 and its Young modulus 2×1011Nm−2. Find the maximum elongation of a half-metre steel wire that can be given without exceeding the elastic limit.

A point mass m is attached at the end of a massless rod of length L. Other end of rod is hinged to frictionless hinge. Sudden velocity V=√9gL2 is provided to the point mass as shown in figure. So hinge reaction when this rod rotates by 1800 is

The circuit shown in the figure contains two diodes D1 and D2 each with a forward resistance of 50 ohms and with infinite backward resistance. If the battery voltage is 6V, the current through the 100 ohm resistance (in Amperes) is:

In the figure shown a current I1 is established in the long straight wire AB. Another wire CD carrying current I2 is placed in the plane of the paper. The line joining the ends of this wire is perpendicular to the wire AB. The resultant force on the wire CD is:

The work done to move 25×1018 electrons between two points is 100 mJ. What is the potential difference between the two points?

Two rods of different materials are kept in series. If temperature of the junction is 30∘C, find K1K2

An object is placed 15 cm in front of a convex lens of focal length 10 cm. Find the nature and position of the image formed. Where should a concave mirror of radius of curvature 20 cm be placed so that the final image is formed at the position of the object itself?

The moment of inertia of a uniform cylinder of length l and radius R about its perpendicular bisector is I. What is the ratio l/R such that the moment of inertia is minimum ?

An insulating sphere of radius R having a cavity of radius R4 at the periphery is charged uniformly with charge Q. If the magnitude of electric field at point 'P' due to the above charge distribution is 8αKQ63R2, then the value of α is (Answer upto two digits after the decimal point)

A rocket has a mass of 1000 kg with 50,000 kg of fuel being stored on this rocket. The nozzle of the rocket lets out the exhaust gases at a speed of 500 m/s. If the rocket consumes fuel at the rate of 100 kg/s, what is the acceleration of the rocket after 5 minutes in a gravity free space?

Two conductors having same width and length, thickness d1 and d2, thermal conductivity K1 and K2 are placed one above the another. Find the equivalent thermal conductivity parallel to the contact surface such that the temperature difference across both the faces of both the conductors are same.

How much work should be done in decreasing the volume of an ideal gas by an amount of 2.4×10−4 m3 at normal temperature and constant pressure of 1×105 N/m2 ?

Can energy be zero in E=mc2 equation? Give reason.

A wire suspended vertically from one end of its ends is stretched by attaching a weight of 200 N to the lower end. The weight stretches the wire by 1 mm. Then the elastic energy stored in the wire(in J) is

A football player kicked a ball with a velocity of 20 ms−1 in a direction making an angle of 60∘ with horizontal. Find the velocity with which he should run in the same direction so that the ball remains above this head.

A body of mass 6 kg user under a force which causes displacement in it given S=t^2/4 meters where t is time . The work done by the force in 2 sec is..?

A block of 2 kg is suspended from the ceiling through a massless spring of spring constant k = 100 N/m. What is the elongation of the spring ? If another 1 kg is added to the block, what would be the further elongation ?

The kinetic energy of a projectile at the highest point of it projection is 75% of its kinetic energy at the point of projection. Find the angle of projection.

In electric flux taken in sphere the electric field and area are taken in same direction when a q positive charge is taken at centre the angle between electric field and the area is 0 then dot product of their will zero or not

A fireman of mass 80 kg slides down a pole during a rescue mission. The force of friction is constant at 720 N. Find the acceleration of the man.

0.216g of an organic compound gave 28.8cm3 of moist nitrogen measured at 288k and 732.7 mm pressure. The percentage of N2 in the substance is approximately (aqueous tension is 12.7mm)