50278 + Interview Questions in Physics

1.	Which of the following will change their time period as they are taken to moon?
Answer» Which of the following will change their time period as they are taken to moon?

Discussion

2.	A body having velocity of 20 m/s towards +ve x-axis collides with a body initially moving with 10 m/s in -ve x-axis direction. If the collision is elastic and the first body is now moving with a velocity of 15 m/s towards -ve x-axis. What is the final velocity of the second body?
Answer» A body having velocity of 20 m/s towards +ve x-axis collides with a body initially moving with 10 m/s in -ve x-axis direction. If the collision is elastic and the first body is now moving with a velocity of 15 m/s towards -ve x-axis. What is the final velocity of the second body?

Discussion

3.	A conducting ring of radius r is rolling without slipping with a constant angular velocity ω as shown in figure. Maximum EMF induced across any arc subtending angle of 60∘ at center of ring is
Answer» A conducting ring of radius $r$ is rolling without slipping with a constant angular velocity $ω$ as shown in figure. Maximum EMF induced across any arc subtending angle of $60^{\circ}$ at center of ring is

Discussion

4.	A car moves towards a hill with speed vc. It blows a horn of frequency f which is heard by an observer following the car with speed v0. The speed of sound in air is v.
Answer» A car moves towards a hill with speed $v_{c}$ . It blows a horn of frequency f which is heard by an observer following the car with speed $v_{0} .$ The speed of sound in air is v.

Discussion

5.	A small ball starts rolling on a inclined track with becomes loop if radius R in vertical plane.
Answer» A small ball starts rolling on a inclined track with becomes loop if radius R in vertical plane.

5.

A small ball starts rolling on a inclined track with becomes loop if radius R in vertical plane.

Answer»

A small ball starts rolling on a inclined track with becomes loop if radius R in vertical plane.

Discussion

6.	Diagram shows an imaginary cube of side a. A uniformly charged rod of length a moves towards right at a constant speed v. At t=0, the right end of the rod just touches the left face of the cube . The graph that best represents the change in electric flux through the cube versus time -
Answer» Diagram shows an imaginary cube of side $a$ . A uniformly charged rod of length $a$ moves towards right at a constant speed $v$ . At $t = 0$ , the right end of the rod just touches the left face of the cube . The graph that best represents the change in electric flux through the cube versus time -

Discussion

7.	A stationary hydrogen atom of mass m in the ground state achieves minimum excitation energy after head-on, inelastic collision with a moving hydrogen atom. Find the velocity of moving hydrogen atom:
Answer» A stationary hydrogen atom of mass m in the ground state achieves minimum excitation energy after head-on, inelastic collision with a moving hydrogen atom. Find the velocity of moving hydrogen atom:

Discussion

8.	A frictionless pulley has radius r. A uniform chain of linear density d and total length (2L+πr) is released from rest over the pulley as shown. When right end is lowered by y=y0 from the mean position, speed of the chain is
Answer» A frictionless pulley has radius r. A uniform chain of linear density d and total length $(2 L + π r)$ is released from rest over the pulley as shown. When right end is lowered by $y = y_{0}$ from the mean position, speed of the chain is

8.

A frictionless pulley has radius r. A uniform chain of linear density d and total length (2L+πr) is released from rest over the pulley as shown. When right end is lowered by y=y0 from the mean position, speed of the chain is

Answer»

A frictionless pulley has radius r. A uniform chain of linear density d and total length $(2 L + π r)$ is released from rest over the pulley as shown. When right end is lowered by $y = y_{0}$ from the mean position, speed of the chain is

Discussion

9.	A boy is moving along a circular track in anticlockwise sense. A point sound source moves along a regular hexagonal path. The centres of hexagonal track and the circular track coincide as shown in the figure. The source and boy starts from point B and A respectively such that P, A & B always lie on the same radial line. At what point, the frequency heard by the boy is minimum?
Answer» A boy is moving along a circular track in anticlockwise sense. A point sound source moves along a regular hexagonal path. The centres of hexagonal track and the circular track coincide as shown in the figure. The source and boy starts from point B and A respectively such that P, A & B always lie on the same radial line. At what point, the frequency heard by the boy is minimum?

9.

A boy is moving along a circular track in anticlockwise sense. A point sound source moves along a regular hexagonal path. The centres of hexagonal track and the circular track coincide as shown in the figure. The source and boy starts from point B and A respectively such that P, A & B always lie on the same radial line. At what point, the frequency heard by the boy is minimum?

Answer»

A boy is moving along a circular track in anticlockwise sense. A point sound source moves along a regular hexagonal path. The centres of hexagonal track and the circular track coincide as shown in the figure. The source and boy starts from point B and A respectively such that P, A & B always lie on the same radial line. At what point, the frequency heard by the boy is minimum?

Discussion

10.	A satellite is revolving around the earth in a circular orbit of radius 'a' with velocity v0. A particle is projected from the statellite in forward direction wiht relative velocity V=[(√54)]v0. During the subsequent motion of the particle, match the following: Column IColumn III. Total energy of particleP.(−3GMem)8aII. Minimum distance ofQ.(−5GMem)8a particle from the earthIII. Maximum distance ofR.5a3 particle from the earthS. 2aT.2a3U. a
Answer» A satellite is revolving around the earth in a circular orbit of radius 'a' with velocity $v_{0}$ . A particle is projected from the statellite in forward direction wiht relative velocity $V = [(\frac{\sqrt{5}}{4})] v_{0} .$ During the subsequent motion of the particle, match the following: $\begin{matrix} Column I & Column II I. Total energy of particle & P. \frac{(- 3 G M_{e} m)}{8 a} II. Minimum distance of & Q. \frac{(- 5 G M_{e} m)}{8 a} particle from the earth III. Maximum distance of & R. \frac{5 a}{3} particle from the earth S. 2a T. \frac{2 a}{3} U. a \end{matrix}$

Discussion

11.	If fa and ff represent the carrier wave frequencies for amplitude and frequency modulations respectively, then
Answer» If $f_{a}$ and $f_{f}$ represent the carrier wave frequencies for amplitude and frequency modulations respectively, then

Discussion

12.	A conductor of mass14kg and length 2 m can move without friction along two metallic parallel tracks in a horizontal plane and connected across a capacitor C = 1000 μ F. The whole system is in a magnetic field of magnetic inductance B = 2 tesla directed outward to the plane. A constant force F = 1.33 N is applied to the middle of conductor perpendicular to it and parallel to the tracks. Find the acceleration of conductor neglecting all resistances. Assume that the conductor started from rest.
Answer» A conductor of mass $\frac{1}{4}$ kg and length 2 m can move without friction along two metallic parallel tracks in a horizontal plane and connected across a capacitor C = 1000 $μ$ F. The whole system is in a magnetic field of magnetic inductance B = 2 tesla directed outward to the plane. A constant force F = 1.33 N is applied to the middle of conductor perpendicular to it and parallel to the tracks. Find the acceleration of conductor neglecting all resistances. Assume that the conductor started from rest.

Discussion

13.	The wall with a cavity consists of two layers of brick separated by a layer of air. All three layers have the same thickness, and the thermal conductivity of the brick is much greater than that of air. The left layer is at a higher temperature than the right layer and steady state condition exists. Which of the following graphs predicts correctly the variation of temperature T with distance d inside the cavity ?
Answer» The wall with a cavity consists of two layers of brick separated by a layer of air. All three layers have the same thickness, and the thermal conductivity of the brick is much greater than that of air. The left layer is at a higher temperature than the right layer and steady state condition exists. Which of the following graphs predicts correctly the variation of temperature $T$ with distance $d$ inside the cavity ?

Discussion

14.	What is gravitational potential energy?
Answer» What is gravitational potential energy?

Discussion

15.	What is the value of a+r+t? Given a→ absorptive power, r→ reflective power, t→ transmissive power.
Answer» What is the value of $a + r + t$ ? Given $a \to$ absorptive power, $r \to$ reflective power, $t \to$ transmissive power.

Discussion

16.	A bus starts from a bus stop with a constant acceleration of 0.4 m/s2. A passenger arrives at the stop 6 sec after bus leaves the stop. Minimum constant speed (in m/s) of passenger so that he can catch bus is (Write upto two digits after the decimal point.)
Answer» A bus starts from a bus stop with a constant acceleration of 0.4 $m / s^{2}$ . A passenger arrives at the stop 6 sec after bus leaves the stop. Minimum constant speed (in m/s) of passenger so that he can catch bus is (Write upto two digits after the decimal point.)

Discussion

17.	A frame is formed by nine identical wires of resistance R each as shown in the figure. The equivalent resistance between A and B is
Answer» A frame is formed by nine identical wires of resistance R each as shown in the figure. The equivalent resistance between A and B is

Discussion

18.	A wire is bent into the form of semicircle of radius R and carry current i. Magnetic field at point P as shown in figure is B=μ0iaπRln(b+c)
Answer» A wire is bent into the form of semicircle of radius R and carry current i. Magnetic field at point P as shown in figure is $B = \frac{μ_{0} i}{a π R} l n (b + c)$

Discussion

19.	Two sound waves with wavelengths 5 m and 5.5 m respectively, propagates in a gas with velocity 330 m/s. The number of beats per second will be
Answer» Two sound waves with wavelengths $5 m$ and $5.5 m$ respectively, propagates in a gas with velocity $330 m/s$ . The number of beats per second will be

Discussion

20.	how to study jee-physics in one year?
Answer» how to study jee-physics in one year?

Discussion

21.	Find d2ydx2 if y=enx
Answer» Find $\frac{d^{2} y}{d x^{2}}$ if $y = e^{n x}$

Discussion

22.	A small body of mass m slides without friction from the top of a hemispherical cup of radius r as shown in the following figure. If it leaves the surface of the cup at a vertical distance h below the highest point, then-
Answer» A small body of mass $m$ slides without friction from the top of a hemispherical cup of radius $r$ as shown in the following figure. If it leaves the surface of the cup at a vertical distance $h$ below the highest point, then-

Discussion

23.	a wire of resistance 18 ohm is bent to form an equilateral triangle. The resistance across any two vertices of the triangle is(in ohm)
Answer» a wire of resistance 18 ohm is bent to form an equilateral triangle. The resistance across any two vertices of the triangle is(in ohm)

Discussion

24.	Three charges +q,-q,-q are placed at the corner of equilateral triangle of side 'a'. The resultant force on a charge+q placed at the centre of the triangle is
Answer» Three charges +q,-q,-q are placed at the corner of equilateral triangle of side 'a'. The resultant force on a charge+q placed at the centre of the triangle is

Discussion

25.	A particle P is sliding down a frictionless hemispherical bowl. It passes the point A at t = 0. At this instant of time, the horizontal component of its velocity is v. A bead Q of the same mass as P is ejected from A at t = 0 along the horizontal string AB, with a speed v. Friction between the bead and the string may be neglected. Let tp and tq be the respective times taken by P and Q to reach the point B. Then
Answer» A particle P is sliding down a frictionless hemispherical bowl. It passes the point A at t = 0. At this instant of time, the horizontal component of its velocity is v. A bead Q of the same mass as P is ejected from A at t = 0 along the horizontal string AB, with a speed v. Friction between the bead and the string may be neglected. Let $t_{p}$ and $t_{q}$ be the respective times taken by P and Q to reach the point B. Then

25.

A particle P is sliding down a frictionless hemispherical bowl. It passes the point A at t = 0. At this instant of time, the horizontal component of its velocity is v. A bead Q of the same mass as P is ejected from A at t = 0 along the horizontal string AB, with a speed v. Friction between the bead and the string may be neglected. Let tp and tq be the respective times taken by P and Q to reach the point B. Then

Answer»

A particle P is sliding down a frictionless hemispherical bowl. It passes the point A at t = 0. At this instant of time, the horizontal component of its velocity is v. A bead Q of the same mass as P is ejected from A at t = 0 along the horizontal string AB, with a speed v. Friction between the bead and the string may be neglected. Let $t_{p}$ and $t_{q}$ be the respective times taken by P and Q to reach the point B. Then

Discussion

26.	Let →a=^i+^j+^k, →b=^i−^j+^k and →c=^i−^j−^k be three vectors. A vector →v in the plane of →a and →b, whose projection on →c is 2√3, is given by
Answer» Let $\to a =^i +^j +^k$ , $\to b =^i -^j +^k$ and $\to c =^i -^j -^k$ be three vectors. A vector $\to v$ in the plane of $\to a$ and $\to b$ , whose projection on $\to c$ is $\frac{2}{\sqrt{3}}$ , is given by

Discussion

27.	A galvanometer coil has a resistance of 15 ohm and the metre shows full scale deflection for a current of 4mA. How will you convert the metre into an ammeter of range 0 to 6 A?
Answer» A galvanometer coil has a resistance of 15 ohm and the metre shows full scale deflection for a current of 4mA. How will you convert the metre into an ammeter of range 0 to 6 A?

Discussion

28.	The velocity of a particle depends upon as v= a+bt+ct2,if the velocity is in m/sec,the unit of a will be?
Answer» The velocity of a particle depends upon as v= a+bt+ct²,if the velocity is in m/sec,the unit of a will be?

Discussion

29.	In a hydrogen atom, the energy of the first excited state is - 3.4 eV. Find out the K.E. of the same orbit of the hydrogen atom.
Answer» In a hydrogen atom, the energy of the first excited state is - 3.4 eV. Find out the K.E. of the same orbit of the hydrogen atom.

Discussion

30.	If wavelengths of maximum intensity of radiations emitted by the sun and the moon are 0.5×10−6m and 10−4m respectively, the ratio of their temperatures is
Answer» If wavelengths of maximum intensity of radiations emitted by the sun and the moon are $0.5 \times 10^{- 6} m$ and $10^{- 4} m$ respectively, the ratio of their temperatures is

Discussion

31.	Can a ball kept on a rough surface be termed as a stable equilibrium state, given friction acts towards the original position upon displacement?
Answer» Can a ball kept on a rough surface be termed as a stable equilibrium state, given friction acts towards the original position upon displacement?

Discussion

32.	A body starting from rest moves with an acceleration of 2 m/s2 for the first 5 seconds and increases its acceleration to 4 m/s2 for the next 8 seconds. Calculate the total distance covered in metres. __
Answer» A body starting from rest moves with an acceleration of 2 $m / s^{2}$ for the first 5 seconds and increases its acceleration to 4 $m / s^{2}$ for the next 8 seconds. Calculate the total distance covered in metres. __

Discussion

33.	Core of electromagnets are made of ferromagnetic material which has
Answer» Core of electromagnets are made of ferromagnetic material which has

Discussion

34.	A particle is moving with constant angular velocity along the circumference of a circle. Which of the following statements is true
Answer» A particle is moving with constant angular velocity along the circumference of a circle. Which of the following statements is true

Discussion

35.	A 2 kg body (initially at rest) is displaced by a variable force F=(3x2+15) N on a rough horizontal plane with coefficient of kinetic friction μ=0.5. Find the speed of the block, after the block has travelled a distance of 5 m.
Answer» A $2 kg$ body (initially at rest) is displaced by a variable force $F = (3 x^{2} + 15) N$ on a rough horizontal plane with coefficient of kinetic friction $μ = 0.5$ . Find the speed of the block, after the block has travelled a distance of $5 m$ .

Discussion

36.	A uniform string of length l is fixed at both ends such that tension T is produced in it. The string is excited to vibrate with maximum displacement amplitude a0. The maximum kinetic energy of the string for its fundamental tone is
Answer» A uniform string of length l is fixed at both ends such that tension T is produced in it. The string is excited to vibrate with maximum displacement amplitude $a_{0}$ . The maximum kinetic energy of the string for its fundamental tone is

36.

A uniform string of length l is fixed at both ends such that tension T is produced in it. The string is excited to vibrate with maximum displacement amplitude a0. The maximum kinetic energy of the string for its fundamental tone is

Answer»

A uniform string of length l is fixed at both ends such that tension T is produced in it. The string is excited to vibrate with maximum displacement amplitude $a_{0}$ .

The maximum kinetic energy of the string for its fundamental tone is

Discussion

37.	The volume of the balloon filled with hydrogen gas, which will be sufficient to lift a load of 24 kg in air is (ρair=0.00129g cc−1,ρH=0.00009g cc−1)
Answer» The volume of the balloon filled with hydrogen gas, which will be sufficient to lift a load of 24 kg in air is $(ρ_{a} i r = 0.00129 g c c^{- 1}, ρ_{H} = 0.00009 g c c^{- 1})$

Discussion

38.	Two perfectly conducting rails 1 and 2 lie perpendicular to a uniform magnetic field B(into the plane of paper as shown). Separation between the rails is l. Two bars AB and CD are placed perpendicular to the rails and move away from one another with velocity v. If the resistance of the bars are R and R2 respectively, the current in the bars is given by xBlv3R. The value of x2 is
Answer» Two perfectly conducting rails $1$ and $2$ lie perpendicular to a uniform magnetic field $B$ (into the plane of paper as shown). Separation between the rails is $l$ . Two bars $A B$ and $C D$ are placed perpendicular to the rails and move away from one another with velocity $v$ . If the resistance of the bars are $R$ and $\frac{R}{2}$ respectively, the current in the bars is given by $\frac{x B l v}{3 R}$ . The value of $x^{2}$ is

Discussion

39.	A uniformly charged thin spherical shell of radius R carries uniform surface charge density of σ per unit area. It is made of two hemispherical shells, held together by pressing them with force F (see figure). F is proportional to:
Answer» A uniformly charged thin spherical shell of radius $R$ carries uniform surface charge density of $σ$ per unit area. It is made of two hemispherical shells, held together by pressing them with force F (see figure). F is proportional to:

Discussion

40.	The magnetic field component of an electromagetic wave propagating through a non-magnetic medium is given by →H=6 cos(2×108t−6x) ^j Am−1 where x,t are in SI units . The relative permittivity of the medium is
Answer» The magnetic field component of an electromagetic wave propagating through a non-magnetic medium is given by $\to H = 6 c o s (2 \times 10^{8} t - 6 x)^j A m^{- 1}$ where $x, t$ are in $S I$ units . The relative permittivity of the medium is

Discussion

41.	The sum of two positive numbers is 20. Find the numbers if their product is maximum
Answer» The sum of two positive numbers is 20. Find the numbers if their product is maximum

Discussion

42.	The average power dissipation in pure inductance is:
Answer» The average power dissipation in pure inductance is:

Discussion

43.	A body is projected horizontally with a velocity of 10 m/s from the top of an inclined plane of angle 45∘. If it is to hit the foot of the plane and acceleration due to gravity is 10 m/s2, the height of the plane (in m ) is
Answer» A body is projected horizontally with a velocity of $10 m/s$ from the top of an inclined plane of angle $45^{\circ}$ . If it is to hit the foot of the plane and acceleration due to gravity is $10 m / s^{2}$ , the height of the plane (in $m$ ) is

Discussion

44.	A ring Of mass M and radium R is placed in the vertical plane and carries a current i. Find the angular acceleration of the ring at this instant if B is the external B - field.
Answer» A ring Of mass M and radium R is placed in the vertical plane and carries a current i. Find the angular acceleration of the ring at this instant if B is the external B - field.

Discussion

45.	Two perfect gases at absolute temperatures T1 and T2 are mixed. There is no loss of energy in this process. If n1 and n2 are the respective number of molecules of the gases, the temperature of the mixture will be
Answer» Two perfect gases at absolute temperatures $T_{1} a n d T_{2}$ are mixed. There is no loss of energy in this process. If $n_{1} a n d n_{2}$ are the respective number of molecules of the gases, the temperature of the mixture will be

Discussion

46.	The work function of the target material is 1.24 eV and the wavelength of incident light is 4360 ∘A. What retarding potential is necessary to stop the emission of the electrons?
Answer» The work function of the target material is $1.24 e V$ and the wavelength of incident light is $4360 \circ A$ . What retarding potential is necessary to stop the emission of the electrons?

Discussion

47.	A particle of mass m is moving along the side of a square of side ‘a’, with a uniform speed v in the x-y plane as shown in the figure: Which of the following statement is false for the angular momentum →L about the origin?
Answer» A particle of mass m is moving along the side of a square of side ‘a’, with a uniform speed v in the x-y plane as shown in the figure: Which of the following statement is false for the angular momentum $\to L$ about the origin?

47.

A particle of mass m is moving along the side of a square of side ‘a’, with a uniform speed v in the x-y plane as shown in the figure: Which of the following statement is false for the angular momentum →L about the origin?

Answer»

A particle of mass m is moving along the side of a square of side ‘a’, with a uniform speed v in the x-y plane as shown in the figure:

Which of the following statement is false for the angular momentum $\to L$ about the origin?

Discussion

48.	An arc AB with the centre C and the infinitely long wire having linear charge density λ are lying in the same plane. Find the minimum amount of work to be done to move a point charge q0 from point A to B through a circular path AB of radius a.
Answer» An arc AB with the centre C and the infinitely long wire having linear charge density $λ$ are lying in the same plane. Find the minimum amount of work to be done to move a point charge $q_{0}$ from point A to B through a circular path AB of radius a.

Discussion

49.	A metal meter scale of breadth 2.5 cm has two holes, each of radius 1 cm, at the two ends. When it is heated, the distance between the holes
Answer» A metal meter scale of breadth 2.5 cm has two holes, each of radius 1 cm, at the two ends. When it is heated, the distance between the holes

Discussion

50.	In the circuit shown, the voltmeter reading is 40 V. Find the value of unknown resistor R
Answer» In the circuit shown, the voltmeter reading is 40 V. Find the value of unknown resistor R

50.

In the circuit shown, the voltmeter reading is 40 V. Find the value of unknown resistor R

Answer»

In the circuit shown, the voltmeter reading is 40 V. Find the value of unknown resistor R

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Which of the following will change their time period as they are taken to moon?

A body having velocity of 20 m/s towards +ve x-axis collides with a body initially moving with 10 m/s in -ve x-axis direction. If the collision is elastic and the first body is now moving with a velocity of 15 m/s towards -ve x-axis. What is the final velocity of the second body?

A conducting ring of radius r is rolling without slipping with a constant angular velocity ω as shown in figure. Maximum EMF induced across any arc subtending angle of 60∘ at center of ring is

A car moves towards a hill with speed vc. It blows a horn of frequency f which is heard by an observer following the car with speed v0. The speed of sound in air is v.

A small ball starts rolling on a inclined track with becomes loop if radius R in vertical plane.

Diagram shows an imaginary cube of side a. A uniformly charged rod of length a moves towards right at a constant speed v. At t=0, the right end of the rod just touches the left face of the cube . The graph that best represents the change in electric flux through the cube versus time -

A stationary hydrogen atom of mass m in the ground state achieves minimum excitation energy after head-on, inelastic collision with a moving hydrogen atom. Find the velocity of moving hydrogen atom:

A frictionless pulley has radius r. A uniform chain of linear density d and total length (2L+πr) is released from rest over the pulley as shown. When right end is lowered by y=y0 from the mean position, speed of the chain is

If fa and ff represent the carrier wave frequencies for amplitude and frequency modulations respectively, then

What is gravitational potential energy?

What is the value of a+r+t? Given a→ absorptive power, r→ reflective power, t→ transmissive power.

A bus starts from a bus stop with a constant acceleration of 0.4 m/s2. A passenger arrives at the stop 6 sec after bus leaves the stop. Minimum constant speed (in m/s) of passenger so that he can catch bus is (Write upto two digits after the decimal point.)

A frame is formed by nine identical wires of resistance R each as shown in the figure. The equivalent resistance between A and B is

A wire is bent into the form of semicircle of radius R and carry current i. Magnetic field at point P as shown in figure is B=μ0iaπRln(b+c)

Two sound waves with wavelengths 5 m and 5.5 m respectively, propagates in a gas with velocity 330 m/s. The number of beats per second will be

how to study jee-physics in one year?

Find d2ydx2 if y=enx

A small body of mass m slides without friction from the top of a hemispherical cup of radius r as shown in the following figure. If it leaves the surface of the cup at a vertical distance h below the highest point, then-

a wire of resistance 18 ohm is bent to form an equilateral triangle. The resistance across any two vertices of the triangle is(in ohm)

Three charges +q,-q,-q are placed at the corner of equilateral triangle of side 'a'. The resultant force on a charge+q placed at the centre of the triangle is

Let →a=^i+^j+^k, →b=^i−^j+^k and →c=^i−^j−^k be three vectors. A vector →v in the plane of →a and →b, whose projection on →c is 2√3, is given by

A galvanometer coil has a resistance of 15 ohm and the metre shows full scale deflection for a current of 4mA. How will you convert the metre into an ammeter of range 0 to 6 A?

The velocity of a particle depends upon as v= a+bt+ct2,if the velocity is in m/sec,the unit of a will be?

In a hydrogen atom, the energy of the first excited state is - 3.4 eV. Find out the K.E. of the same orbit of the hydrogen atom.

If wavelengths of maximum intensity of radiations emitted by the sun and the moon are 0.5×10−6m and 10−4m respectively, the ratio of their temperatures is

Can a ball kept on a rough surface be termed as a stable equilibrium state, given friction acts towards the original position upon displacement?

A body starting from rest moves with an acceleration of 2 m/s2 for the first 5 seconds and increases its acceleration to 4 m/s2 for the next 8 seconds. Calculate the total distance covered in metres. __

Core of electromagnets are made of ferromagnetic material which has

A particle is moving with constant angular velocity along the circumference of a circle. Which of the following statements is true

A 2 kg body (initially at rest) is displaced by a variable force F=(3x2+15) N on a rough horizontal plane with coefficient of kinetic friction μ=0.5. Find the speed of the block, after the block has travelled a distance of 5 m.

A uniform string of length l is fixed at both ends such that tension T is produced in it. The string is excited to vibrate with maximum displacement amplitude a0. The maximum kinetic energy of the string for its fundamental tone is

The volume of the balloon filled with hydrogen gas, which will be sufficient to lift a load of 24 kg in air is (ρair=0.00129g cc−1,ρH=0.00009g cc−1)

A uniformly charged thin spherical shell of radius R carries uniform surface charge density of σ per unit area. It is made of two hemispherical shells, held together by pressing them with force F (see figure). F is proportional to:

The magnetic field component of an electromagetic wave propagating through a non-magnetic medium is given by →H=6 cos(2×108t−6x) ^j Am−1 where x,t are in SI units . The relative permittivity of the medium is

The sum of two positive numbers is 20. Find the numbers if their product is maximum

The average power dissipation in pure inductance is:

A body is projected horizontally with a velocity of 10 m/s from the top of an inclined plane of angle 45∘. If it is to hit the foot of the plane and acceleration due to gravity is 10 m/s2, the height of the plane (in m ) is

A ring Of mass M and radium R is placed in the vertical plane and carries a current i. Find the angular acceleration of the ring at this instant if B is the external B - field.

Two perfect gases at absolute temperatures T1 and T2 are mixed. There is no loss of energy in this process. If n1 and n2 are the respective number of molecules of the gases, the temperature of the mixture will be

The work function of the target material is 1.24 eV and the wavelength of incident light is 4360 ∘A. What retarding potential is necessary to stop the emission of the electrons?

A particle of mass m is moving along the side of a square of side ‘a’, with a uniform speed v in the x-y plane as shown in the figure: Which of the following statement is false for the angular momentum →L about the origin?

An arc AB with the centre C and the infinitely long wire having linear charge density λ are lying in the same plane. Find the minimum amount of work to be done to move a point charge q0 from point A to B through a circular path AB of radius a.

A metal meter scale of breadth 2.5 cm has two holes, each of radius 1 cm, at the two ends. When it is heated, the distance between the holes

In the circuit shown, the voltmeter reading is 40 V. Find the value of unknown resistor R