50278 + Interview Questions in Physics

1.	16.To paint the side of a building a painter normally hosts himself up by pulling on the rope A as shown in figute.The paintercand tge platform together weigh 200N. The eope B can withstand 300N.find a)maximum acceleration of painter b)tension in rope A when painter is at rest
Answer» 16.To paint the side of a building a painter normally hosts himself up by pulling on the rope A as shown in figute.The paintercand tge platform together weigh 200N. The eope B can withstand 300N.find a)maximum acceleration of painter b)tension in rope A when painter is at rest

Discussion

2.	The air tight and smooth pistons of a cylindrical vessel are connected with a string as shown. Initially pressure and temperature of the gas are P∘ and T∘. The atmospheric pressure is also P∘. At a later time, tension in the string is 38 P∘A, where A is the cross sectional area of the cylinder. At this time, the temperature of the gas has become
Answer» The air tight and smooth pistons of a cylindrical vessel are connected with a string as shown. Initially pressure and temperature of the gas are $P_{\circ}$ and $T_{\circ}$ . The atmospheric pressure is also $P_{\circ}$ . At a later time, tension in the string is $\frac{3}{8} P_{\circ} A$ , where $A$ is the cross sectional area of the cylinder. At this time, the temperature of the gas has become

Discussion

3.	The angular velocity of flywheel changes from 240 rpm to 120 rpm in 6 seconds. Calculate the no. of revolutions it will make before coming to rest
Answer» The angular velocity of flywheel changes from 240 rpm to 120 rpm in 6 seconds. Calculate the no. of revolutions it will make before coming to rest

Discussion

4.	Two projectiles are projected at angles (π4+θ) and (π4−θ) with the horizontal, where θ<π4, with same speed. The ratio of horizontal ranges described by them is
Answer» Two projectiles are projected at angles $(\frac{π}{4} + θ) and (\frac{π}{4} - θ)$ with the horizontal, where $θ < \frac{π}{4}$ , with same speed. The ratio of horizontal ranges described by them is

Discussion

5.	A 2.00 m - long rope, having a mass of 80 g, is fixed at one end and is tied to a light string at the other end. The tension in the string is 256 N. (a) Find the frequencies of the fundamental and the first two overtones. (b) Find the wavelength in the fundamental and the first two overtones.
Answer» A 2.00 m - long rope, having a mass of 80 g, is fixed at one end and is tied to a light string at the other end. The tension in the string is 256 N. (a) Find the frequencies of the fundamental and the first two overtones. (b) Find the wavelength in the fundamental and the first two overtones.

Discussion

6.	If \|→a\|=\|→b\|=\|→c\|=2 and →a⋅→b=→b⋅→c=→c⋅→a=2, then [→a →b →c]cos45∘ is equal to
Answer» If $\| \to a \| = \| \to b \| = \| \to c \| = 2$ and $\to a \cdot \to b = \to b \cdot \to c = \to c \cdot \to a = 2,$ then $[\to a \to b \to c] cos 45^{\circ}$ is equal to

Discussion

7.	An iron nail is dropped from a height h from the level of a sand bed. If it penetrates through a distance x in the sand before coming to rest, the average force exerted by the sand on the nail is,
Answer» An iron nail is dropped from a height h from the level of a sand bed. If it penetrates through a distance x in the sand before coming to rest, the average force exerted by the sand on the nail is,

Discussion

8.	A 40 μF capacitor is connected to a 200 V ac source. The RMS value of the current in the circuit is 2.5 A then the frequency of the AC source is (nearly)
Answer» A $40 μ F$ capacitor is connected to a $200 V$ ac source. The RMS value of the current in the circuit is $2.5 A$ then the frequency of the AC source is (nearly)

Discussion

9.	For one mole of a van der Waals gas for which b=0 and T=300 K, the PV vs 1V plot is shown below. The value of the van der Waals constant a (in atm L mol−2) is:
Answer» For one mole of a van der Waals gas for which $b = 0$ and $T = 300 K$ , the $P V vs \frac{1}{V}$ plot is shown below. The value of the van der Waals constant $a$ (in ${atm L mol}^{- 2}$ ) is:

Discussion

10.	The force of attraction between the positively charged nucleus and the electron in a hydrogen atom is given by F=ke2r2. Assume that the nucleus is fixed. The electron, initially moving in an orbit of radius R1 jumps into an orbit of smaller radius R2. The decrease in the total energy of the atom is-
Answer» The force of attraction between the positively charged nucleus and the electron in a hydrogen atom is given by $F = k \frac{e^{2}}{r^{2}}$ . Assume that the nucleus is fixed. The electron, initially moving in an orbit of radius $R_{1}$ jumps into an orbit of smaller radius $R_{2} .$ The decrease in the total energy of the atom is-

Discussion

11.	The x and y co-ordinates of a particle at any time are x=5t2−3t+6 and y=10t2+2t+3 respectively, where x and y are in meters and t in seconds. Find the acceleration of the particle at t=1s.
Answer» The $x$ and $y$ co-ordinates of a particle at any time are $x = 5 t^{2} - 3 t + 6$ and $y = 10 t^{2} + 2 t + 3$ respectively, where $x$ and $y$ are in meters and $t$ in seconds. Find the acceleration of the particle at $t = 1 s$ .

Discussion

12.	Given below are some functions of x and t to represent the displacement (transverse or longitudinal) of an elastic wave. State which of these represent (i) a traveling wave, (ii) a stationary wave or (iii) none at all: (a) y = 2 cos (3x) sin (10t) (b) y=2√x−vt (c) y = 3 sin (5x – 0.5t) + 4 cos (5x – 0.5t) (d) y = cos x sin t + cos 2x sin 2t
Answer» Given below are some functions of x and t to represent the displacement (transverse or longitudinal) of an elastic wave. State which of these represent (i) a traveling wave, (ii) a stationary wave or (iii) none at all: (a) y = 2 cos (3x) sin (10t) (b) $y = 2 \sqrt{x - v t}$ (c) y = 3 sin (5x – 0.5t) + 4 cos (5x – 0.5t) (d) y = cos x sin t + cos 2x sin 2t

Discussion

13.	White light is used to illuminate the two slits in Young's double slit experiment. The separation between the slits is b and the screen is at a distance d (>>b) from the slits. At a point on the screen directly in front of one of the slits, certain wavelengths are missing. some of these missing wavelengths are
Answer» White light is used to illuminate the two slits in Young's double slit experiment. The separation between the slits is $b$ and the screen is at a distance $d (>> b)$ from the slits. At a point on the screen directly in front of one of the slits, certain wavelengths are missing. some of these missing wavelengths are

Discussion

14.	A particle is undergoing circular motion with angular frequency ω as shown If the shadow of the particle on the wall is performing SHM such that its acceleration's maximum value is 'a', find the acceleration of the particle and the radius of the circle.
Answer» A particle is undergoing circular motion with angular frequency $ω$ as shown If the shadow of the particle on the wall is performing SHM such that its acceleration's maximum value is 'a', find the acceleration of the particle and the radius of the circle.

14.

A particle is undergoing circular motion with angular frequency ω as shown If the shadow of the particle on the wall is performing SHM such that its acceleration's maximum value is 'a', find the acceleration of the particle and the radius of the circle.

Answer»

A particle is undergoing circular motion with angular frequency $ω$ as shown

If the shadow of the particle on the wall is performing SHM such that its acceleration's maximum value is 'a', find the acceleration of the particle and the radius of the circle.

Discussion

15.	A block of mass 2√3 kg rests on a horizontal frictionless plane. What would be the acceleration of the block if it is subjected to two forces (in same horizontal plane) as shown in figure?
Answer» A block of mass $2 \sqrt{3} kg$ rests on a horizontal frictionless plane. What would be the acceleration of the block if it is subjected to two forces $($ in same horizontal plane $)$ as shown in figure?

Discussion

16.	List I gives some physical quantites and List II gives some possible graphs symbols have usual meaning i.e., a, v, x, t stands for acceleration, velocity, position and time for given v - x graph correct match is
Answer» List I gives some physical quantites and List II gives some possible graphs symbols have usual meaning i.e., a, v, x, t stands for acceleration, velocity, position and time for given v - x graph correct match is

Discussion

17.	A 1.0 m long metallic rod is rotated with an angular frequency of 400 rad s−1 about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic field of 0.5 T parallel to the axis exists everywhere. Calculate the emf developed between the centre and the ring.
Answer» A 1.0 m long metallic rod is rotated with an angular frequency of 400 rad s⁻¹about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic field of 0.5 T parallel to the axis exists everywhere. Calculate the emf developed between the centre and the ring.

Discussion

18.	A convex lens made of glass of refractive index 1.5 has both surfaces of the same radius of curvature R. In case (i) the lens is immersed in a medium of refractive index 1.25 and in case (ii) it is immersed in a medium of refractive index 1.75. Then,
Answer» A convex lens made of glass of refractive index 1.5 has both surfaces of the same radius of curvature R. In case (i) the lens is immersed in a medium of refractive index 1.25 and in case (ii) it is immersed in a medium of refractive index 1.75. Then,

Discussion

19.	A particle of mass m having a charge q enters into a circular region of radius R with velocity v directed towards the centre. The strength of magnetic field is B. Find the deviation in the path of the particle.
Answer» A particle of mass m having a charge q enters into a circular region of radius R with velocity v directed towards the centre. The strength of magnetic field is B. Find the deviation in the path of the particle.

Discussion

20.	13.The three rods have identical geometric dimensions . Heat flows from hot end at rate of 40W in arrangement 1 . Find the rate of heat flow in arrangement 2 . Kb = 2KA.
Answer» 13.The three rods have identical geometric dimensions . Heat flows from hot end at rate of 40W in arrangement 1 . Find the rate of heat flow in arrangement 2 . Kb = 2KA.

Discussion

21.	If intensity of incident light is increased in PEE then which of the following is true
Answer» If intensity of incident light is increased in PEE then which of the following is true

Discussion

22.	A body of mass m falls from rest from height of R/4above the earth's surface, where R is the radius ofearth. Kinetic energy of the body just before it touches the earth's surface is \lbrack g accelerationdue to gravity on the surface of earth\rbrack
Answer» A body of mass m falls from rest from height of R/4above the earth's surface, where R is the radius ofearth. Kinetic energy of the body just before it touches the earth's surface is \lbrack g accelerationdue to gravity on the surface of earth\rbrack

Discussion

23.	the difference between heats of reaction at cons†an t pressure and cons†an t volume for the reaction 2C6H6(l)+15 O2(g)→12 Co2(g)+6 H2(l)at 25^° C in KJ is
Answer» the difference between heats of reaction at cons†an t pressure and cons†an t volume for the reaction 2C6H6(l)+15 O2(g)→12 Co2(g)+6 H2(l)at 25^° C in KJ is

Discussion

24.	An inductor (L=0.03 H) and a resistor (R=0.15 kΩ) are connected in series to a battery of 15 V emf in a circuit shown below. The key K1 has been kept closed for a long time. Then at t=0,K1 is opened and key K2 is closed simultaneously. At t=1 ms, the current in the circuit will be (e5≅150)
Answer» An inductor ( $L = 0.03 H$ ) and a resistor ( $R = 0.15 k Ω$ ) are connected in series to a battery of $15 V$ emf in a circuit shown below. The key $K_{1}$ has been kept closed for a long time. Then at $t = 0, K_{1}$ is opened and key $K_{2}$ is closed simultaneously. At $t = 1 m s$ , the current in the circuit will be $(e^{5} ≅ 150)$

Discussion

25.	Block of mass 4 kg is placed on rough horizontal plane a time dependent horizontal force f is equal to 2 t acts on the block the frictional force between the block and the plane with the time t is equal to 2 seconds is(u=0.2)
Answer» Block of mass 4 kg is placed on rough horizontal plane a time dependent horizontal force f is equal to 2 t acts on the block the frictional force between the block and the plane with the time t is equal to 2 seconds is(u=0.2)

Discussion

26.	3 identical masses are released from rest. What will be their velocities when the separation between any 2 masses becomes a/2 ?
Answer» $3$ identical masses are released from rest. What will be their velocities when the separation between any $2$ masses becomes $a / 2$ ?

Discussion

27.	Figure shows a 2.0 V potentiometer used for the determinationof internal resistance of a 1.5 V cell. The balance point of the cell inopen circuit is 76.3 cm. When a resistor of 9.5 W is used in the externalcircuit of the cell, the balance point shifts to 64.8 cm length of thepotentiometer wire. Determine the internal resistance of the cell.
Answer» Figure shows a 2.0 V potentiometer used for the determinationof internal resistance of a 1.5 V cell. The balance point of the cell inopen circuit is 76.3 cm. When a resistor of 9.5 W is used in the externalcircuit of the cell, the balance point shifts to 64.8 cm length of thepotentiometer wire. Determine the internal resistance of the cell.

Discussion

28.	The incident photon involved in the photoelectric effect experiment.
Answer» The incident photon involved in the photoelectric effect experiment.

Discussion

29.	An equiconvex glass lens of focal length 24 cm is placed on a plane mirror. An object coincides with its image when it is at a height of 24 cm from the lens. The gap between the lens and the mirror is filled with water (μw=4/3). The focal length of the water-lens thus formed is 72 cm. By how much distance should the object be now shifted so that it again coincides with its image ? (μg=1.5)
Answer» An equiconvex glass lens of focal length $24 cm$ is placed on a plane mirror. An object coincides with its image when it is at a height of $24 cm$ from the lens. The gap between the lens and the mirror is filled with water $(μ_{w} = 4 / 3)$ . The focal length of the water-lens thus formed is $72 cm$ . By how much distance should the object be now shifted so that it again coincides with its image ? $(μ_{g} = 1.5)$

Discussion

30.	You have a bar magnet and you are given an iron strip. How will you make the iron strip a magnet?
Answer» You have a bar magnet and you are given an iron strip. How will you make the iron strip a magnet?

Discussion

31.	An equiconvex glass lens has a focal length f and power P. It is cut into two symmetrical halves by a plane containing the principal axis. The two pieces are recombined by keeping side by side. What is the power of new combination.
Answer» An equiconvex glass lens has a focal length f and power P. It is cut into two symmetrical halves by a plane containing the principal axis. The two pieces are recombined by keeping side by side. What is the power of new combination.

Discussion

32.	For the figure shown below, the coefficient of friction between 2 kg and 4 kg block is 0.1 and between 4 kg and ground is 0.2. The graph of friction force acting on 4 kg block by the ground as a function of time is
Answer» For the figure shown below, the coefficient of friction between $2 k g$ and $4 k g$ block is $0.1$ and between $4 k g$ and ground is $0.2$ . The graph of friction force acting on $4 k g$ block by the ground as a function of time is

Discussion

33.	Gaussian surface cannot pass through the Any discrete charges as r tends to infinity E not defined but how Gaussian surface can't pass through continuous charge distribution explain this point (continuous charge distribution)
Answer» Gaussian surface cannot pass through the Any discrete charges as r tends to infinity E not defined but how Gaussian surface can't pass through continuous charge distribution explain this point (continuous charge distribution)

Discussion

34.	Consider two concentric spherical sürfaces S1, with radius a and S2 with radius 2a, both centered at the origin. There is a charge +q at the origin and there is no other charges. If flux through surfaces S1 and S2 are ϕ1 and ϕ2 respectively, then.(1) ϕ1=ϕ2/2(2) ϕ1=ϕ2 3)ϕ1=2ϕ2 4)ϕ1=4ϕ
Answer» Consider two concentric spherical sürfaces S1, with radius a and S2 with radius 2a, both centered at the origin. There is a charge +q at the origin and there is no other charges. If flux through surfaces S1 and S2 are ϕ1 and ϕ2 respectively, then.(1) ϕ1=ϕ2/2(2) ϕ1=ϕ2 3)ϕ1=2ϕ2 4)ϕ1=4ϕ

Discussion

35.	150.Focal length of concave mirror is f and distance of object from principal focus is P. Ratio of size of image & object wil be
Answer» 150.Focal length of concave mirror is f and distance of object from principal focus is P. Ratio of size of image & object wil be

Discussion

36.	how the ratio of radii of second orbit of hydrogen atom to first orbit is 2:1
Answer» how the ratio of radii of second orbit of hydrogen atom to first orbit is 2:1

Discussion

37.	An infinite number of identical charges, each +q coulomb, are placed along x-axis at x=1 m,3 m,9 m,... Calculate the electric field at the point x=0 due to these charges.
Answer» An infinite number of identical charges, each $+ q coulomb$ , are placed along $x-$ axis at $x = 1 m, 3 m, 9 m, . . .$ Calculate the electric field at the point $x = 0$ due to these charges.

Discussion

38.	The energy required to excite an electron from n=2 to n=3 energy state is 47.2 eV. The charge number of the nucleus, around which the electron revolving, will be-
Answer» The energy required to excite an electron from $n = 2$ to $n = 3$ energy state is $47.2 eV$ . The charge number of the nucleus, around which the electron revolving, will be-

Discussion

39.	Can i get the answer for the question, A rnachine gun of l5 kg fires 0.02 kg bullets at the rate of l0 per second with a speed of 300 m/s. Calculate the force required to hold the gun in position.
Answer» Can i get the answer for the question, A rnachine gun of l5 kg fires 0.02 kg bullets at the rate of l0 per second with a speed of 300 m/s. Calculate the force required to hold the gun in position.

Discussion

40.	6. Find the time taken by current to reach the root mean square value from t=0 to t' then value of t' is 1/1200s 1/250s 1/200s 1/800s Equation of alternating current is:
Answer» 6. Find the time taken by current to reach the root mean square value from t=0 to t' then value of t' is 1/1200s 1/250s 1/200s 1/800s Equation of alternating current is:

Discussion

41.	60.The angle between the direction of propagation and the plane of polarisation is 0 degree(not 90) . Why?
Answer» 60.The angle between the direction of propagation and the plane of polarisation is 0 degree(not 90) . Why?

Discussion

42.	184. A ball of mass 50 g is thrown upwards. It rises to 9 a maximum height of 100 m. At what height its kinetic energy will be reduced to 70%? (1) 30 m (3) 60 m (2) 40 m (4) 70 m
Answer» 184. A ball of mass 50 g is thrown upwards. It rises to 9 a maximum height of 100 m. At what height its kinetic energy will be reduced to 70%? (1) 30 m (3) 60 m (2) 40 m (4) 70 m

Discussion

43.	Number of electrons in one coulomb of charge will be
Answer» Number of electrons in one coulomb of charge will be

Discussion

44.	The magnetic field at center, P will be
Answer» The magnetic field at center, $P$ will be

Discussion

45.	A body situated on the surface of the earth of mass M and radius R, at it's equator, become weightless, when the rotational kinetic energy of earth, reaches a critical value K.find the value of K?
Answer» A body situated on the surface of the earth of mass M and radius R, at it's equator, become weightless, when the rotational kinetic energy of earth, reaches a critical value K.find the value of K?

Discussion

46.	A body executing shm with amplitude a and time period t .the ratio of kinetic energy and potential energy when displacement from the equilibrium position is half the amplitude
Answer» A body executing shm with amplitude a and time period t .the ratio of kinetic energy and potential energy when displacement from the equilibrium position is half the amplitude

Discussion

47.	Let Fpp and Fnn denote the net magnitudes of forces between a proton and a proton, a proton and a neutron, and between two neutrons, when they are 1fm apart. Which is the correct relation?
Answer» Let $F_{p p}$ and $F_{n n}$ denote the net magnitudes of forces between a proton and a proton, a proton and a neutron, and between two neutrons, when they are $1 f m$ apart. Which is the correct relation?

Discussion

48.	Twelve resistors each of resistance r are connected together so that each lies along the edge of the cube as shown in the figure. The equivalent resistance between points 1 and 3 is
Answer» Twelve resistors each of resistance $r$ are connected together so that each lies along the edge of the cube as shown in the figure. The equivalent resistance between points $1$ and $3$ is

Discussion

49.	When the temperature of a black body increases, it is observed that the wavelength corresponding to maximum energy changes from 0.26 mm to 0.13 mm. The ratio of the emissive powers of the body at the respective temperature is
Answer» When the temperature of a black body increases, it is observed that the wavelength corresponding to maximum energy changes from $0.26 mm$ to $0.13 mm$ . The ratio of the emissive powers of the body at the respective temperature is

Discussion

50.	Express the velocity of an electron in the n-th orbit of the hydrogen atom, in terms of the principal quantum number n itself.
Answer» Express the velocity of an electron in the n-th orbit of the hydrogen atom, in terms of the principal quantum number n itself.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

16.To paint the side of a building a painter normally hosts himself up by pulling on the rope A as shown in figute.The paintercand tge platform together weigh 200N. The eope B can withstand 300N.find a)maximum acceleration of painter b)tension in rope A when painter is at rest

The angular velocity of flywheel changes from 240 rpm to 120 rpm in 6 seconds. Calculate the no. of revolutions it will make before coming to rest

Two projectiles are projected at angles (π4+θ) and (π4−θ) with the horizontal, where θ&lt;π4, with same speed. The ratio of horizontal ranges described by them is

A 2.00 m - long rope, having a mass of 80 g, is fixed at one end and is tied to a light string at the other end. The tension in the string is 256 N. (a) Find the frequencies of the fundamental and the first two overtones. (b) Find the wavelength in the fundamental and the first two overtones.

If |→a|=|→b|=|→c|=2 and →a⋅→b=→b⋅→c=→c⋅→a=2, then [→a →b →c]cos45∘ is equal to

An iron nail is dropped from a height h from the level of a sand bed. If it penetrates through a distance x in the sand before coming to rest, the average force exerted by the sand on the nail is,

A 40 μF capacitor is connected to a 200 V ac source. The RMS value of the current in the circuit is 2.5 A then the frequency of the AC source is (nearly)

For one mole of a van der Waals gas for which b=0 and T=300 K, the PV vs 1V plot is shown below. The value of the van der Waals constant a (in atm L mol−2) is:

The x and y co-ordinates of a particle at any time are x=5t2−3t+6 and y=10t2+2t+3 respectively, where x and y are in meters and t in seconds. Find the acceleration of the particle at t=1s.

A particle is undergoing circular motion with angular frequency ω as shown If the shadow of the particle on the wall is performing SHM such that its acceleration's maximum value is 'a', find the acceleration of the particle and the radius of the circle.

A block of mass 2√3 kg rests on a horizontal frictionless plane. What would be the acceleration of the block if it is subjected to two forces (in same horizontal plane) as shown in figure?

List I gives some physical quantites and List II gives some possible graphs symbols have usual meaning i.e., a, v, x, t stands for acceleration, velocity, position and time for given v - x graph correct match is

A convex lens made of glass of refractive index 1.5 has both surfaces of the same radius of curvature R. In case (i) the lens is immersed in a medium of refractive index 1.25 and in case (ii) it is immersed in a medium of refractive index 1.75. Then,

A particle of mass m having a charge q enters into a circular region of radius R with velocity v directed towards the centre. The strength of magnetic field is B. Find the deviation in the path of the particle.

13.The three rods have identical geometric dimensions . Heat flows from hot end at rate of 40W in arrangement 1 . Find the rate of heat flow in arrangement 2 . Kb = 2KA.

If intensity of incident light is increased in PEE then which of the following is true

A body of mass m falls from rest from height of R/4above the earth's surface, where R is the radius ofearth. Kinetic energy of the body just before it touches the earth's surface is \lbrack g accelerationdue to gravity on the surface of earth\rbrack

the difference between heats of reaction at cons†an t pressure and cons†an t volume for the reaction 2C6H6(l)+15 O2(g)→12 Co2(g)+6 H2(l)at 25^° C in KJ is

An inductor (L=0.03 H) and a resistor (R=0.15 kΩ) are connected in series to a battery of 15 V emf in a circuit shown below. The key K1 has been kept closed for a long time. Then at t=0,K1 is opened and key K2 is closed simultaneously. At t=1 ms, the current in the circuit will be (e5≅150)

Block of mass 4 kg is placed on rough horizontal plane a time dependent horizontal force f is equal to 2 t acts on the block the frictional force between the block and the plane with the time t is equal to 2 seconds is(u=0.2)

3 identical masses are released from rest. What will be their velocities when the separation between any 2 masses becomes a/2 ?

The incident photon involved in the photoelectric effect experiment.

You have a bar magnet and you are given an iron strip. How will you make the iron strip a magnet?

An equiconvex glass lens has a focal length f and power P. It is cut into two symmetrical halves by a plane containing the principal axis. The two pieces are recombined by keeping side by side. What is the power of new combination.

For the figure shown below, the coefficient of friction between 2 kg and 4 kg block is 0.1 and between 4 kg and ground is 0.2. The graph of friction force acting on 4 kg block by the ground as a function of time is

Gaussian surface cannot pass through the Any discrete charges as r tends to infinity E not defined but how Gaussian surface can't pass through continuous charge distribution explain this point (continuous charge distribution)

Consider two concentric spherical sürfaces S1, with radius a and S2 with radius 2a, both centered at the origin. There is a charge +q at the origin and there is no other charges. If flux through surfaces S1 and S2 are ϕ1 and ϕ2 respectively, then.(1) ϕ1=ϕ2/2(2) ϕ1=ϕ2 3)ϕ1=2ϕ2 4)ϕ1=4ϕ

150.Focal length of concave mirror is f and distance of object from principal focus is P. Ratio of size of image & object wil be

how the ratio of radii of second orbit of hydrogen atom to first orbit is 2:1

An infinite number of identical charges, each +q coulomb, are placed along x-axis at x=1 m,3 m,9 m,... Calculate the electric field at the point x=0 due to these charges.

The energy required to excite an electron from n=2 to n=3 energy state is 47.2 eV. The charge number of the nucleus, around which the electron revolving, will be-

Can i get the answer for the question, A rnachine gun of l5 kg fires 0.02 kg bullets at the rate of l0 per second with a speed of 300 m/s. Calculate the force required to hold the gun in position.

6. Find the time taken by current to reach the root mean square value from t=0 to t' then value of t' is 1/1200s 1/250s 1/200s 1/800s Equation of alternating current is:

60.The angle between the direction of propagation and the plane of polarisation is 0 degree(not 90) . Why?

184. A ball of mass 50 g is thrown upwards. It rises to 9 a maximum height of 100 m. At what height its kinetic energy will be reduced to 70%? (1) 30 m (3) 60 m (2) 40 m (4) 70 m

Number of electrons in one coulomb of charge will be

The magnetic field at center, P will be

A body situated on the surface of the earth of mass M and radius R, at it's equator, become weightless, when the rotational kinetic energy of earth, reaches a critical value K.find the value of K?

A body executing shm with amplitude a and time period t .the ratio of kinetic energy and potential energy when displacement from the equilibrium position is half the amplitude

Let Fpp and Fnn denote the net magnitudes of forces between a proton and a proton, a proton and a neutron, and between two neutrons, when they are 1fm apart. Which is the correct relation?

Twelve resistors each of resistance r are connected together so that each lies along the edge of the cube as shown in the figure. The equivalent resistance between points 1 and 3 is

When the temperature of a black body increases, it is observed that the wavelength corresponding to maximum energy changes from 0.26 mm to 0.13 mm. The ratio of the emissive powers of the body at the respective temperature is

Express the velocity of an electron in the n-th orbit of the hydrogen atom, in terms of the principal quantum number n itself.

Two projectiles are projected at angles (π4+θ) and (π4−θ) with the horizontal, where θ<π4, with same speed. The ratio of horizontal ranges described by them is