50278 + Interview Questions in Physics

1.	Light in certain cases may be considered as a stream of particles called photons. Each photon has a linear momentum hλ where h is the Planck's constant and λ is the wavelength of the light. A beam of light of wavelength λ is incident on a plane mirror at an angle of incidence θ. Calculate the change in the linear momentum of a photon as the beam is reflected by the mirror.
Answer» Light in certain cases may be considered as a stream of particles called photons. Each photon has a linear momentum $\frac{h}{λ}$ where h is the Planck's constant and $λ$ is the wavelength of the light. A beam of light of wavelength $λ$ is incident on a plane mirror at an angle of incidence $θ$ . Calculate the change in the linear momentum of a photon as the beam is reflected by the mirror.

Discussion

2.	Resultant of two vectors →A and →B is of magnitude P. If →B is reversed, then resultant is of magnitude Q. What is the value of P2+Q2?
Answer» Resultant of two vectors $\to A$ and $\to B$ is of magnitude P. If $\to B$ is reversed, then resultant is of magnitude Q. What is the value of $P^{2} + Q^{2}$ ?

Discussion

3.	The average separation between the proton and the electron in a hydrogen atom in ground state is 5.3×10−11 m (a) Calculate the Coulomb force between them at this separation. (b) When the atom goes into its first excited state the average separation between the proton and the electron increases to four times its value in the ground state. What is the Coulomb force in this state?
Answer» The average separation between the proton and the electron in a hydrogen atom in ground state is $5.3 \times 10^{- 11 m}$ (a) Calculate the Coulomb force between them at this separation. (b) When the atom goes into its first excited state the average separation between the proton and the electron increases to four times its value in the ground state. What is the Coulomb force in this state?

Discussion

4.	A steel rod is rigidly clamped at its two ends. The rod is under zero tension at 20∘ C. If the temperature rises to 100∘ C, what force will the rod exert on one of the clamps? Area of cross section of the rod = 2.0 mm2. Coefficient of linear expansion of steel =12.0×10−6 ∘ C−1 and Young's modulus of steel = 2.00×1011 Nm−2.
Answer» A steel rod is rigidly clamped at its two ends. The rod is under zero tension at $20^{\circ} C$ . If the temperature rises to $100^{\circ} C$ , what force will the rod exert on one of the clamps? Area of cross section of the rod = $2.0 m m^{2}$ . Coefficient of linear expansion of steel $= 12.0 \times 10^{- 6}^{\circ} C^{- 1}$ and Young's modulus of steel = $2.00 \times 10^{11} N m^{- 2}$ .

Discussion

5.	One end of a long metallic wire of length L is tied to the ceiling. The other end is tied to mass less spring of spring constant K. A mass m hangs freely from the free end of the spring. The area of cross-section and Young's modulus of the wire are A and Y respectively. If the mass is slightly pulled down and released, it will oscillate with a time period T equal to
Answer» One end of a long metallic wire of length L is tied to the ceiling. The other end is tied to mass less spring of spring constant K. A mass m hangs freely from the free end of the spring. The area of cross-section and Young's modulus of the wire are A and Y respectively. If the mass is slightly pulled down and released, it will oscillate with a time period T equal to

Discussion

6.	Two resistance R1 and R2 are made of different materials. The temperature coefficient of the material of R1 is α and that of the material of R2 is β . The resistance of the series combination of R2 and R1 does not change with temperature, then the ratio of resistances of the two wires at 0o will be:
Answer» Two resistance $R_{1}$ and $R_{2}$ are made of different materials. The temperature coefficient of the material of $R_{1}$ is $α$ and that of the material of $R_{2}$ is $β$ . The resistance of the series combination of $R_{2}$ and $R_{1}$ does not change with temperature, then the ratio of resistances of the two wires at $0^{o}$ will be:

6.

Two resistance R1 and R2 are made of different materials. The temperature coefficient of the material of R1 is α and that of the material of R2 is β . The resistance of the series combination of R2 and R1 does not change with temperature, then the ratio of resistances of the two wires at 0o will be:

Answer»

Two resistance $R_{1}$ and $R_{2}$ are made of different materials. The temperature coefficient of the material of $R_{1}$ is $α$ and that of the material of $R_{2}$ is $β$ . The resistance of the series combination of $R_{2}$ and $R_{1}$ does not change with temperature, then the ratio of resistances of the two wires at $0^{o}$ will be:

Discussion

7.	A resistance of R Ω draws current from a potentiometer as shown in the figure. The potentiometer has a total resistance R0 Ω. A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of the potentiometer.
Answer» A resistance of R $Ω$ draws current from a potentiometer as shown in the figure. The potentiometer has a total resistance $R_{0} Ω$ . A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of the potentiometer.

Discussion

8.	A N-type semiconductor is
Answer» A N-type semiconductor is

Discussion

9.	At a constant temperature what should be the percentage increase in pressure for a 5% decrease in the volume of gas?
Answer» At a constant temperature what should be the percentage increase in pressure for a $5 %$ decrease in the volume of gas?

Discussion

10.	A ruler is accurate when the temperature is 25∘C. When the temperature drops to −15∘C, the ruler shrinks and no longer measures distances accurately.However the ruler can be made to read correctly if a force of magnitude 1.2×103 N applied to each end so as to stretch it back to its original length. The ruler has a cross sectional area of 1.6×10−5 m2, and it is made from a material whose coefficient of linear expansion is 2.5×10−5(C∘)−1. What is Young's modulus (in 109 N/m2) for the material from which the ruler is made?
Answer» A ruler is accurate when the temperature is $25^{\circ} C$ . When the temperature drops to $- 15^{\circ} C$ , the ruler shrinks and no longer measures distances accurately.However the ruler can be made to read correctly if a force of magnitude $1.2 \times 10^{3} N$ applied to each end so as to stretch it back to its original length. The ruler has a cross sectional area of $1.6 \times 10^{- 5} m^{2}$ , and it is made from a material whose coefficient of linear expansion is $2.5 \times 10^{- 5} (C^{\circ})^{- 1}$ . What is Young's modulus (in $10^{9} {N/m}^{2}$ ) for the material from which the ruler is made?

Discussion

11.	Intensity of magnetic field due to earth at a point inside a hollow steel box is
Answer» Intensity of magnetic field due to earth at a point inside a hollow steel box is

Discussion

12.	A simple pendulum 1m long has a Bob of 10kg. If the pendulum swings from a horizontal position, the KE of the Bob at the instant it passes through the lowest position of it's path is
Answer» A simple pendulum 1m long has a Bob of 10kg. If the pendulum swings from a horizontal position, the KE of the Bob at the instant it passes through the lowest position of it's path is

Discussion

13.	A light metal disc on the top of an electromagnet is thrown up as the current is switched on. Why ? Give reason.
Answer» A light metal disc on the top of an electromagnet is thrown up as the current is switched on. Why ? Give reason.

Discussion

14.	A conical pendulum of length L makes an angle θ with the vertical. The time period will be
Answer» A conical pendulum of length L makes an angle $θ$ with the vertical. The time period will be

Discussion

15.	Let A(0, 6, 6), B(6,6, 0) and C(6, 0, 6) are three points and the point D is moving on the line x + z – 3 = 0 = y. If G is centroid of bigtriangleupABC, then minimum value of GD is ___________
Answer» Let A(0, 6, 6), B(6,6, 0) and C(6, 0, 6) are three points and the point D is moving on the line x + z – 3 = 0 = y. If G is centroid of $b i g t r i a n g l e u p$ ABC, then minimum value of GD is ___________

Discussion

16.	The specific heat of argon at constant volume is 0.075 kcal/kg K. Calculate its atomic weight [ R=2 cal/mol K ]
Answer» The specific heat of argon at constant volume is $0.075 kcal/kg K$ . Calculate its atomic weight [ $R = 2 cal/mol K$ ]

Discussion

17.	A long straight wire carries a current I0=100 amp.A particle having a positive charge q=100C and mass m=10g is kept at a distance x0=10m from the wire is projected away from it with a speed v0=10m/sec. The maximum separation between particle and wire is found to be y( 10) m. Find y. [Take e100=3]. ___
Answer» A long straight wire carries a current $I_{0} = 100$ amp.A particle having a positive charge q=100C and mass m=10g is kept at a distance $x_{0} = 10 m$ from the wire is projected away from it with a speed $v_{0} = 10 m / s e c$ . The maximum separation between particle and wire is found to be y( 10) m. Find y. $[T a k e e^{100} = 3]$ . ___

Discussion

18.	Identify the graph of the function y = {x} or x - [x]
Answer» Identify the graph of the function y = {x} or x - [x]

Discussion

19.	Find the moment of inertia of a solid cylinder of length l, radius R, about the central axis parallel to the height of the cylinder. The density of the cylinder varies with radius as ρ=2r.
Answer» Find the moment of inertia of a solid cylinder of length $l$ , radius $R$ , about the central axis parallel to the height of the cylinder. The density of the cylinder varies with radius as $ρ = 2 r$ .

Discussion

20.	Calculate Reynold’s number, if a fluid having a viscosity of 0.4 Ns/m2 and density of 900 kg/m3 flows through a pipe of length 20 mm with a velocity of 2.5 m/s.
Answer» Calculate Reynold’s number, if a fluid having a viscosity of $0.4 {Ns/m}^{2}$ and density of $900 {kg/m}^{3}$ flows through a pipe of length $20 mm$ with a velocity of $2.5 m/s$ .

Discussion

21.	The translational kinetic energy of 1 mole of an ideal gas at standard temperature is close to
Answer» The translational kinetic energy of $1 mole$ of an ideal gas at standard temperature is close to

Discussion

22.	Find the projection of →A=10^i+8^j−6^k along →r=5^i+6^j+9^k
Answer» Find the projection of $\to A = 10^i + 8^j - 6^k$ along $\to r = 5^i + 6^j + 9^k$

Discussion

23.	In a situation shown below, if the speed of the tip of the seconds hand is v m/s, find the magnitude of change in its velocity.
Answer» In a situation shown below, if the speed of the tip of the seconds hand is $v m/s$ , find the magnitude of change in its velocity.

Discussion

24.	A gramophone record of mass M and radius R is rotating with angular speed ω. If two pieces of wax each of mass m are kept on it at a distance R2 from the centre on opposite sides, then the new angular velocity will be
Answer» A gramophone record of mass $M$ and radius $R$ is rotating with angular speed $ω$ . If two pieces of wax each of mass $m$ are kept on it at a distance $\frac{R}{2}$ from the centre on opposite sides, then the new angular velocity will be

Discussion

25.	One plate of a capacitor is connected to a spring as shown in Fig. Area of both the plates is A. In steady state separation between the plates is 0.8 d (spring was un stretched and the distance between the plates was d when the capacitor was uncharged). The force constant of the spring is
Answer» One plate of a capacitor is connected to a spring as shown in Fig. Area of both the plates is A. In steady state separation between the plates is 0.8 d (spring was un stretched and the distance between the plates was d when the capacitor was uncharged). The force constant of the spring is

Discussion

26.	A total charge Q is broken in two parts Q1 and Q2 and they are placed at a distance R from each other. The maximum force of repulsion between them will occur, when
Answer» A total charge $Q$ is broken in two parts $Q_{1}$ and $Q_{2}$ and they are placed at a distance $R$ from each other. The maximum force of repulsion between them will occur, when

Discussion

27.	Two bodies of masses m1 and m2 are connected by a light, inextensible string, which passes over a frictionless pulley. If the pulley is moving upward with uniform acceleration g, then the tension in the string is
Answer» Two bodies of masses m₁ and m₂ are connected by a light, inextensible string, which passes over a frictionless pulley. If the pulley is moving upward with uniform acceleration g, then the tension in the string is

Discussion

28.	A charged particle is projected with velocity →v=u^i from the origin, in a region having electric field →E and magnetic field →B both. Value of →B and →E are given in column 1 and column 2 respectively and path of the particle is given in column 3. Column 1 Column 2 Column 3 (Magnetic field) (Electric field) (Path of particle)(i)→B=0(i)→E=0(P)Circular path(ii)→B=B0^i+B0^j(ii)→E=E0^i(Q)Helical path(iii)→B=B0^j+B0^k(iii)→E=B0u(^j−^k)(R)Cycloid(iv)→B=B0^k(iv)→E=E0^k(S)Straight line Which of the following combination is correct?
Answer» A charged particle is projected with velocity $\to v = u^i$ from the origin, in a region having electric field $\to E$ and magnetic field $\to B$ both. Value of $\to B$ and $\to E$ are given in column 1 and column 2 respectively and path of the particle is given in column 3. $\begin{matrix} Column 1 & Column 2 & Column 3 (Magnetic field) & (Electric field) & (Path of particle) (i) & \to B = 0 & (i) & \to E = 0 & (P) & Circular path (i i) & \to B = B_{0}^i + B_{0}^j & (i i) & \to E = E_{0}^i & (Q) & Helical path (i i i) & \to B = B_{0}^j + B_{0}^k & (i i i) & \to E = B_{0} u (^j -^k) & (R) & Cycloid (i v) & \to B = B_{0}^k & (i v) & \to E = E_{0}^k & (S) & Straight line \end{matrix}$ Which of the following combination is correct?

28.

A charged particle is projected with velocity →v=u^i from the origin, in a region having electric field →E and magnetic field →B both. Value of →B and →E are given in column 1 and column 2 respectively and path of the particle is given in column 3. Column 1 Column 2 Column 3 (Magnetic field) (Electric field) (Path of particle)(i)→B=0(i)→E=0(P)Circular path(ii)→B=B0^i+B0^j(ii)→E=E0^i(Q)Helical path(iii)→B=B0^j+B0^k(iii)→E=B0u(^j−^k)(R)Cycloid(iv)→B=B0^k(iv)→E=E0^k(S)Straight line Which of the following combination is correct?

Answer»

A charged particle is projected with velocity $\to v = u^i$ from the origin, in a region having electric field $\to E$ and magnetic field $\to B$ both. Value of $\to B$ and $\to E$ are given in column 1 and column 2 respectively and path of the particle is given in column 3.

$\begin{matrix} Column 1 & Column 2 & Column 3 (Magnetic field) & (Electric field) & (Path of particle) (i) & \to B = 0 & (i) & \to E = 0 & (P) & Circular path (i i) & \to B = B_{0}^i + B_{0}^j & (i i) & \to E = E_{0}^i & (Q) & Helical path (i i i) & \to B = B_{0}^j + B_{0}^k & (i i i) & \to E = B_{0} u (^j -^k) & (R) & Cycloid (i v) & \to B = B_{0}^k & (i v) & \to E = E_{0}^k & (S) & Straight line \end{matrix}$

Which of the following combination is correct?

Discussion

29.	O2 is 16 times heavier than H2. If at the same temperature the O2 molecules have average kinetic energy E, then at the same temperature the average kinetic energy of H2 molecules will be
Answer» $O_{2}$ is $16$ times heavier than $H_{2}$ . If at the same temperature the $O_{2}$ molecules have average kinetic energy $E,$ then at the same temperature the average kinetic energy of $H_{2}$ molecules will be

Discussion

30.	A circular spring of natural length l is cut and welded with two beads of masses m1 and m2 such that the ratio of the lengths of the springs between the beads is 4:1. If the stiffness of the original spring is k, then find the angular frequency of oscillation of the beads in a smooth horizontal rigid tube. [Assume m1=m and m2=3m].
Answer» A circular spring of natural length $l$ is cut and welded with two beads of masses $m_{1}$ and $m_{2}$ such that the ratio of the lengths of the springs between the beads is $4 : 1$ . If the stiffness of the original spring is $k$ , then find the angular frequency of oscillation of the beads in a smooth horizontal rigid tube. [Assume $m_{1} = m$ and $m_{2} = 3 m$ ].

Discussion

31.	Three identical circular planner disc each of mass m and radius r are welded as shown in figure. The moment of inertia of the arrangement about the axis normal to the plane and passing through the point P is
Answer» Three identical circular planner disc each of mass $m$ and radius $r$ are welded as shown in figure. The moment of inertia of the arrangement about the axis normal to the plane and passing through the point $P$ is

Discussion

32.	An object is moving in a straight-line path has a velocity of 40 m/s at some instant. After 10 s, its velocity changed to 80 m/s. What is the average acceleration of the ball during this time interval?
Answer» An object is moving in a straight-line path has a velocity of $40 m/s$ at some instant. After $10 s$ , its velocity changed to $80 m/s$ . What is the average acceleration of the ball during this time interval?

Discussion

33.	A 1,000 kg car moving at a speed of 20ms is brought to rest in a distance of 50 m, calculate the net force acting on the car.
Answer» A 1,000 kg car moving at a speed of $20 \frac{m}{s}$ is brought to rest in a distance of 50 m, calculate the net force acting on the car.

Discussion

34.	Why does the resistance increase on increasing temperature
Answer» Why does the resistance increase on increasing temperature

Discussion

35.	A train has each compartment of mass ‘m′ is accelerating uniformly. The velocity of the engine is V1 and the velocity of the last compartment is V2. Find the velocity of the compartment in the middle when it passes the same mile marker assuming that the compartments are of point sizes.
Answer» A train has each compartment of mass $‘ m^{'}$ is accelerating uniformly. The velocity of the engine is $V_{1}$ and the velocity of the last compartment is $V_{2}$ . Find the velocity of the compartment in the middle when it passes the same mile marker assuming that the compartments are of point sizes.

Discussion

36.	In the arrangement of three blocks as shown in the figure, the string is inextensible. If the directions of accelerations are as shown in the given figure, and a1+a2=na3, then find n.
Answer» In the arrangement of three blocks as shown in the figure, the string is inextensible. If the directions of accelerations are as shown in the given figure, and $a_{1} + a_{2} = n a_{3}$ , then find $n$ .

Discussion

37.	A Centigrade and Fahrenheit thermometers are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers a temperature of 140 ∘F. The fall of the temperature as registered by the centigrade thermometer is:
Answer» A Centigrade and Fahrenheit thermometers are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers a temperature of $140^{\circ} F$ . The fall of the temperature as registered by the centigrade thermometer is:

Discussion

38.	Which of the statements are correct 1) the sum of the kinetic energy and potential energy is called the total mechanical energy 2) the sum total of energy in a system is constant
Answer» Which of the statements are correct 1) the sum of the kinetic energy and potential energy is called the total mechanical energy 2) the sum total of energy in a system is constant

38.

Which of the statements are correct 1) the sum of the kinetic energy and potential energy is called the total mechanical energy 2) the sum total of energy in a system is constant

Answer»

Which of the statements are correct

1) the sum of the kinetic energy and potential energy is called the total mechanical energy

2) the sum total of energy in a system is constant

Discussion

39.	Two particles move parallel to x axis about the origin with the same amplitude and frequency at a certain instant they are found at a distance from the origin on opposite sides but they velocities are found to be in the same direction What is the phase difference between the two
Answer» Two particles move parallel to x axis about the origin with the same amplitude and frequency at a certain instant they are found at a distance from the origin on opposite sides but they velocities are found to be in the same direction What is the phase difference between the two

Discussion

40.	If fof (x)=(1+tans quare xsquare)power 1÷2xpower4 is continuous atx=0 thenfof (0)=
Answer» If fof (x)=(1+tans quare xsquare)power 1÷2xpower4 is continuous atx=0 thenfof (0)=

Discussion

41.	A solid sphere of mass 2 kg is resting inside a cube as shown in the figure. The cube is moving with a velocity v=(5t^i+2t^j) m/s.Here t is the time in second. All surfaces are smooth. The sphere is at rest with respect to the cube. What is the total force exerted by the sphere on the cube. (Take g=10 m/s2).
Answer» A solid sphere of mass 2 kg is resting inside a cube as shown in the figure. The cube is moving with a velocity $v = (5 t^i + 2 t^j) m / s$ .Here $t$ is the time in second. All surfaces are smooth. The sphere is at rest with respect to the cube. What is the total force exerted by the sphere on the cube. (Take $g = 10 m / s^{2}) .$

41.

A solid sphere of mass 2 kg is resting inside a cube as shown in the figure. The cube is moving with a velocity v=(5t^i+2t^j) m/s.Here t is the time in second. All surfaces are smooth. The sphere is at rest with respect to the cube. What is the total force exerted by the sphere on the cube. (Take g=10 m/s2).

Answer»

A solid sphere of mass 2 kg is resting inside a cube as shown in the figure. The cube is moving with a velocity $v = (5 t^i + 2 t^j) m / s$ .Here $t$ is the time in second. All surfaces are smooth. The sphere is at rest with respect to the cube. What is the total force exerted by the sphere on the cube. (Take $g = 10 m / s^{2}) .$

Discussion

42.	The velocity v and displacement x of a particle executing simple harmonic motion are related as vdvdx=−ω2x At x=0,v=v0. Find the velocity v when the displacement becomes x.
Answer» The velocity v and displacement x of a particle executing simple harmonic motion are related as $v \frac{d v}{d x} = - ω^{2} x$ At $x = 0, v = v_{0}$ . Find the velocity v when the displacement becomes x.

42.

The velocity v and displacement x of a particle executing simple harmonic motion are related as vdvdx=−ω2x At x=0,v=v0. Find the velocity v when the displacement becomes x.

Answer»

The velocity v and displacement x of a particle executing simple harmonic motion are related as

$v \frac{d v}{d x} = - ω^{2} x$

At $x = 0, v = v_{0}$ . Find the velocity v when the displacement becomes x.

Discussion

43.	Find the integrals of the functions. ∫(1−cosx)1+cosxdx.
Answer» Find the integrals of the functions. $\int \frac{(1 - c o s x)}{1 + c o s x} d x .$

Discussion

44.	The speed of an electron having a wavelength of 10−10m is
Answer» The speed of an electron having a wavelength of $10^{- 10} m$ is

Discussion

45.	A 1200 kg automobile rounds a level curve of radius 200 m, on an unbanked road with a velocity of 72 km/h. What is the minimum coefficient of static friction between the tyres and road in order that the automobile may not skid? (g=10 m/s2)
Answer» A $1200 kg$ automobile rounds a level curve of radius $200 m$ , on an unbanked road with a velocity of $72 km/h$ . What is the minimum coefficient of static friction between the tyres and road in order that the automobile may not skid? $(g = 10 {m/s}^{2})$

Discussion

46.	A string of length 1 m is fixed at one end with a bob of mass 100 g and the string makes (2π) rev s−1 around a vertical axis through a fixed point. The angle of inclination of the string with the vertical is
Answer» A string of length $1 m$ is fixed at one end with a bob of mass $100 g$ and the string makes $(\frac{2}{π}) {rev s}^{- 1}$ around a vertical axis through a fixed point. The angle of inclination of the string with the vertical is

Discussion

47.	Absolute pressure is related to gauge pressure as?
Answer» Absolute pressure is related to gauge pressure as?

Discussion

48.	A planet of mass m moves around the sun of mass M in an elliptical orbit .The maximum and minimum distances of the planet from sun are r1 and r2 respectively. The time period of the planet is proportional to
Answer» A planet of mass m moves around the sun of mass M in an elliptical orbit .The maximum and minimum distances of the planet from sun are r1 and r2 respectively. The time period of the planet is proportional to

Discussion

49.	What is the difference between a physical quantity and dimensions? Like.. length, mass and time are both physical quantity and dimensions? Then, what's the difference between them?
Answer» What is the difference between a physical quantity and dimensions? Like.. length, mass and time are both physical quantity and dimensions? Then, what's the difference between them?

49.

What is the difference between a physical quantity and dimensions? Like.. length, mass and time are both physical quantity and dimensions? Then, what's the difference between them?

Answer»

What is the difference between a physical quantity and dimensions?

Like.. length, mass and time are both physical quantity and dimensions? Then, what's the difference between them?

Discussion

50.	The sum of vectors A, D and E will be
Answer» The sum of vectors A, D and E will be

50.

The sum of vectors A, D and E will be

Answer»

The sum of vectors A, D and E will be

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Resultant of two vectors →A and →B is of magnitude P. If →B is reversed, then resultant is of magnitude Q. What is the value of P2+Q2?

A resistance of R Ω draws current from a potentiometer as shown in the figure. The potentiometer has a total resistance R0 Ω. A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of the potentiometer.

A N-type semiconductor is

At a constant temperature what should be the percentage increase in pressure for a 5% decrease in the volume of gas?

Intensity of magnetic field due to earth at a point inside a hollow steel box is

A simple pendulum 1m long has a Bob of 10kg. If the pendulum swings from a horizontal position, the KE of the Bob at the instant it passes through the lowest position of it's path is

A light metal disc on the top of an electromagnet is thrown up as the current is switched on. Why ? Give reason.

A conical pendulum of length L makes an angle θ with the vertical. The time period will be

Let A(0, 6, 6), B(6,6, 0) and C(6, 0, 6) are three points and the point D is moving on the line x + z – 3 = 0 = y. If G is centroid of bigtriangleupABC, then minimum value of GD is ___________

The specific heat of argon at constant volume is 0.075 kcal/kg K. Calculate its atomic weight [ R=2 cal/mol K ]

Identify the graph of the function y = {x} or x - [x]

Find the moment of inertia of a solid cylinder of length l, radius R, about the central axis parallel to the height of the cylinder. The density of the cylinder varies with radius as ρ=2r.

Calculate Reynold’s number, if a fluid having a viscosity of 0.4 Ns/m2 and density of 900 kg/m3 flows through a pipe of length 20 mm with a velocity of 2.5 m/s.

The translational kinetic energy of 1 mole of an ideal gas at standard temperature is close to

Find the projection of →A=10^i+8^j−6^k along →r=5^i+6^j+9^k

In a situation shown below, if the speed of the tip of the seconds hand is v m/s, find the magnitude of change in its velocity.

A gramophone record of mass M and radius R is rotating with angular speed ω. If two pieces of wax each of mass m are kept on it at a distance R2 from the centre on opposite sides, then the new angular velocity will be

One plate of a capacitor is connected to a spring as shown in Fig. Area of both the plates is A. In steady state separation between the plates is 0.8 d (spring was un stretched and the distance between the plates was d when the capacitor was uncharged). The force constant of the spring is

A total charge Q is broken in two parts Q1 and Q2 and they are placed at a distance R from each other. The maximum force of repulsion between them will occur, when

Two bodies of masses m1 and m2 are connected by a light, inextensible string, which passes over a frictionless pulley. If the pulley is moving upward with uniform acceleration g, then the tension in the string is

O2 is 16 times heavier than H2. If at the same temperature the O2 molecules have average kinetic energy E, then at the same temperature the average kinetic energy of H2 molecules will be

Three identical circular planner disc each of mass m and radius r are welded as shown in figure. The moment of inertia of the arrangement about the axis normal to the plane and passing through the point P is

An object is moving in a straight-line path has a velocity of 40 m/s at some instant. After 10 s, its velocity changed to 80 m/s. What is the average acceleration of the ball during this time interval?

A 1,000 kg car moving at a speed of 20ms is brought to rest in a distance of 50 m, calculate the net force acting on the car.

Why does the resistance increase on increasing temperature

A train has each compartment of mass ‘m′ is accelerating uniformly. The velocity of the engine is V1 and the velocity of the last compartment is V2. Find the velocity of the compartment in the middle when it passes the same mile marker assuming that the compartments are of point sizes.

In the arrangement of three blocks as shown in the figure, the string is inextensible. If the directions of accelerations are as shown in the given figure, and a1+a2=na3, then find n.

A Centigrade and Fahrenheit thermometers are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers a temperature of 140 ∘F. The fall of the temperature as registered by the centigrade thermometer is:

Which of the statements are correct 1) the sum of the kinetic energy and potential energy is called the total mechanical energy 2) the sum total of energy in a system is constant

Two particles move parallel to x axis about the origin with the same amplitude and frequency at a certain instant they are found at a distance from the origin on opposite sides but they velocities are found to be in the same direction What is the phase difference between the two

If fof (x)=(1+tans quare xsquare)power 1÷2xpower4 is continuous atx=0 thenfof (0)=

The velocity v and displacement x of a particle executing simple harmonic motion are related as vdvdx=−ω2x At x=0,v=v0. Find the velocity v when the displacement becomes x.

Find the integrals of the functions. ∫(1−cosx)1+cosxdx.

The speed of an electron having a wavelength of 10−10m is

A 1200 kg automobile rounds a level curve of radius 200 m, on an unbanked road with a velocity of 72 km/h. What is the minimum coefficient of static friction between the tyres and road in order that the automobile may not skid? (g=10 m/s2)

A string of length 1 m is fixed at one end with a bob of mass 100 g and the string makes (2π) rev s−1 around a vertical axis through a fixed point. The angle of inclination of the string with the vertical is

Absolute pressure is related to gauge pressure as?

A planet of mass m moves around the sun of mass M in an elliptical orbit .The maximum and minimum distances of the planet from sun are r1 and r2 respectively. The time period of the planet is proportional to

What is the difference between a physical quantity and dimensions? Like.. length, mass and time are both physical quantity and dimensions? Then, what's the difference between them?

The sum of vectors A, D and E will be