Physics Questions

A partition divides a container having insulated walls into two compartments I and II The same gas fills the two compartments see Fig The ratio of the number of molecules in compartments I and II is ya fue dart ist m area fearger ergen at CI P V T ima a A 1 6 B 6 1 C 4 1 D 1 4 2P 2V T

RADIATION STEFEN S LAW AND WEIN S LAW A metallic sphere having radius 0 08 m and mass m 10kg is heated to a temperature of 227 C and suspended insic a box whose walls are at a temperature of 27 C The maximum rate at which its temperature will fall is Take e 1 Stefan s constant o 5 8 x 10 Wm K and specific heat of the metal s 90 cal kg deg J 4 2 Joule Calorie 1 055 C sec Atalay So the for wha 4 0 03 C sec BC 2 066 C sec 3 044 C sec

4 For the combination shown in figure which one of the given statements is wrong 1 A 0 and B 0 Y 0 2 A 0 and B 1 Y 0 A 3 A 1 and B 0 Y 1 4 A 1 and B 1 Y 0

Let there be four articles having colours blue red black and white When they are heated together and allowed to cool which article will cool at the earliest RPMT 2007 1 Blue 2 Red 3 Black on of red glass when heated in dark to red hot states will appear to be 4 White Be care of radiation RPMT 20071

In the figure two cells have equal emf E but internal resistance are r and r If the reading of voltmeter is zero then the relation between R r and r is vai fax emffem arafer var ar af alcenter an www A R 1 1 B R 1 1 C 2R 1 1 D R Your Answer

A particle perform SHM of amplitude A along a straight line When it is at a distance of A from its mean position Its kinetic energy gets increased by 2 amount ma 4 due to an impulsive force The new amplitude of the particle becomes O 2A O PA OA

XD a 2 c 3 d 4 b A body takes 4 minutes to cool from 100 C to 70 C To cool from 70 C to 40 C it will take room temperature is 15 C 1 7 minutes A verge 2 6 minutes 3 5 minutes 4 4 minutes 80 C to 60 C in one minute The ambient temperature is 30 C In cooling from 60 C to 50

If the visible region of the spectrum is taken to be wavelengths longer than 400 nm and shorter than 700 nm the number of lines in the hydrogen spectrum which lie in the visible region is A 2 B 3 C 4 D

The range of frequency allotted for FM radio is FM fay ang at A 88 to 108 kHz B 88 to 108 MHz C 88 to 108 GHz D 88 to 108 GHz Your Answer B

Select false statement for standing transverse mechanical waves on a string A Total energy between two nodes remains constant fa aft find i B Total kinetic energy between two nodes ramians constant ufafa alat D faut fed r C Total potential energy between two nodes varies with time af Potential energy of small section at antinodes is constant at frafa fara sa

A black body is at room tempreture It is placed in a furnace and it is observed that 1 In begining it is seen most black and later on it is seen most brightest 2 It is always seen black 3 It can t be resolved at any times 4 In begining it is seen most black and later on it can t be resolved

A long solenoid with 1000 turns per meter has a core with a relative permeability of 500 If the current in the windings is 2 A the values of Hand Mare respectively A 8 x10 A m and 9 98 105 A m B 2x10 A m and 9 98 105 A madong 8381 C 2 10 A m and 10 A m D 8 x10 A m and 106 A m 3

NY75 C 2 3 33 C Two spheres of different materials one having radius double of other and wall thickness 1 4 of other are filled with ice If time required to completely melt the ice is 25 min for larger radius sphere and 16 min for smaller radius sphere then ratio of thermal conduction coefficient for material of larger radius to that of thermal conduction coefficient for mate rial of smaller radius sphere will be 1 4 5 2 5 4 3 8 25 1 1 25 It is placed in a furnace and it is observed that RPMT 2010 RPMT 2010

Which of the following is more close to a black body Black board paint 2 Green leaves 3 Black holes 4 Red roses A black body is at a temperature of 2800 K The energy of radiation emitted by this object wi

d toy The power radiated by a black body is P and it radiates maximum energy at wavelength If the temperature of the black Zo body is now changed so that it radiates maximum energy at wavelength the power radiated by it becomes nP The NEET 2018 X3 256 81 value of n is 1 3 4 2 4 3 4 81 256

The intensity at the maximum in a YDSE is I Distance between two slits is d 52 where is the wavelength of light used in the experiment What will be the intensity in front of one of the slits on the screen placed at a distance D 10d NEET I 2016 4 1 1 1 2 10 JCC 2 3 I

Consider two infinitely long wires parallel to the z axis carrying the same current I Y One wire passes through the point L with coordinates 1 1 and the other through M with coordinates 1 1 in the XY planes shown in the figure The direction of the current in both the wires is in the positive z direction a Find the value of B d along the semicircular closed path of radius 2 units shown in the figure L 1 1 M 1 1 b A third long wire carrying current and also perpendicular to the XY plane is placed at a point N with coordinates x 0 so that the magnetic field at the origin is doubled Find x and the direction of the current in the third wire

Light of wavelength 500 nm travelling with a speed of 2 0 108 ms in a certain medium enters another medium of refractive index 5 4 times that of the first medium What are the wavelength and speed in the second medium Wavelength nm 500 nm Y f Wavelength nm A Speed ms 2 0 108 ms qu meng v n sa faccen 400 B 400 C 500 D 625 Speed ms Your Answer 1 6 108 2 5 108 2 5 108 1 6 108 A Correct Answer

3 It can t be resolved at any tin 4 In begining it is seen most black and later on it can t be resolved What is the mode of heat transfer by which a hot cup of coffee looses most of its heat 2 convection 3 evaporation 4 radiation 1 condiction Which one of the following processes depends on gravity RPMT 2014 AIPMT 2000

A jet of water with cross section of 6 cm strikes a wa at an angle of 60 to the normal and rebounds elastically from the wall without losing energy If the velocity of the water in the jet is 12 m s the force acting on the wall is 0 864 N 86 4 N 72 N 7 2 N

It is hotter at the same distance over the top of a fire than it is on the side of it mainly because 1 heat is rediated upwards 2 Air conducts heat upwards 3 convection takes more heat upwards 4 Conduction convection and radiation all contribute significantly in transferring heat upwards

There are 64 identical drops of a conducting fluid Each drop is charged to potential Vo They are combined to form a bigger drop Potential of bigger drop is nVo Find n Answer 0 8 0 8 1 02 03 4 5 6 9 7 1 2 3 4 5 9 5 6 7

4 For a black body at temperature 727 C its radiating power is 60 watt and temperature of surrounding is 227 C If temperature of black body is changed to 1227 C then its radiating power will be AIPMT 2002 1 304 W 2 320 W 3 240 W 4 120 W lon oxpress relation between AIPMT 2002

4 4 First increases becomes maximum and then Three identical charges are placed at the corners of an equilateral triangle If the force between an charges is F then the net force on each will be 1 2 F 2 2F 3 3 F 4 3F

Three metal rods made of copper aluminium and brass each 20 cm long and 4 cm in diameter are placed end to en with aluminium between the other two The free ends of copper and brass are maintained at 100 and 0 C respectivel Assume that the thermal conductivity of copper is twice that of aluminium and four times that of brass The equilibrium temperatures of the copper aluminium and aluminium brass junctions are respectively 1 68 C and 75 C 2 75 C and 68 C 3 57 C and 86 C 4 86 C and 57 C

Black body spectrum is 1 Continuous spectrum with black lines 3 Continuous spectrum 4 None of the above 6 a despert 2 Continuous spectrum with black band

Assuming the sun to have a spherical outer surface of radius r radiating like a black body at temperature t C the power received by a unit surface normal to the incident rays at a distance R from the center of the sun is Salan Constar 4 r t R 16 r ot 1 2 r t 273 4 R 3 R A black body is at 727 C It emits energy at a rate which is proprotional to r t 273 4 R S Ts Rs R

Internal energy of n moles of hydrogen at temperature T is equal to the internal energy of n2 moles of helium at temperature 2T The value of ratio is neglect vibrational modes in hydrogen n 613

If Cp and Cy denoted the specific heat of unit gram mass of nitrogen at constant pressure and volume respectively then R is universal gas constant O Cp Cy R O Cp Cy 7R 28 Cp Cv R Cp Cy 28R

1 Q 4nR G 2 Q 4nR 0 1 2 3 4TR Q o 4 4 Q 4nR 0 A slab of stone of area 0 36 m and thickness 0 1 m is exposed on the lower surface to steam at 100 C A block of ice at 0 C rests on the upper surface of the slab In one hour 4 8 kg of ice is melted The thermal conductivity of slab is Given latent heat of fusion of ice 3 36 x 10 J kg AIPMT 2012 1 24 J m s C 2 1 29 J m s C 3 2 05 J m s C 4 1 02 J m s C Certain quantity of water cools from 70 C to 60 C in the first 5 minutes and to 54 C in the next 5 minutes The tem

A cyclic process for one mole of an ideal gas is shown in the V T diagram The work done by the gas in AB BC and CA respectively are V Zero RT In O RT In V V RT B A RT RT In VR1 V V Zero T R T1 T RT V V Zero 16

Illustration 1 7 Show that the minimum size of a plane mirror required to see the full image of an observer is half the size of that observer Sol Let HF is the height of the man and E is the eye level Draw the rays HM and FM incident at the edges of the mirror Complete the ray diagram as shown in Fig 1 17 It is self explanatory if you consider lengths x and y as shown in the figure

1 white 2 red 3 green The earth radiates in the infra red region of the specturm The spectrum is correctly given by XLRayleigh Jeans law 2 Planck s law of radiation 3 Stefan s law of radiation 4 Wien s law Nouton s law of cooling the rate of cooling of a body is proportional to 40 where 40 i RE

A disc of mass m and radius R rotates centre of mass with constant angular speed w Its centre of mass moves with a constant velocity v parallel to the x axis as shown At an instant its centre of mass has the coordinates 1 b Its angular momentum about O at that instant is Moment of Inertia of disc about c o m c 1 mvb 3 w mvl 00 V X 2 w mvb 4 Lo myl

Out of six particles two particles have speed of 3 units and other two particles have speed of 5 units The remaining two particles have speed of 2 units and 6 units The r m s speed of the gas molecule is nearly 1 4 units 2 4 24 units 3 9 6 units 4 4 30 units

One end of a metal rod of length 1 0m and area of cross section 100 cm is maintained at 100 C If the other end of the rod is maintained at 0 C the quantity of heat transmitted through the rod per minute will be coefficient of thermal conductivity of materal of rod 100W Kg K 1 3 x 10 J 2 6 x 10 J 3 9 x 10 J 4 12 x 10 J T AT R NORA

A box of negligible mass containing n moles of an ideal gas of molar mass M and adiabatic exponent Y moves with constant speed v on a smooth horizont surface If box suddenly stops then change in temperature of gas will be 7 1 Mv 4R O Y 1 Mv 8R O 7 1 Mv 2R Mv 2 y 1 R

The figure shows consisting of two metals welded together The inner core has a radius R while the outer metal occupies the region from R to 2R in meters The inner core carries a total current of 1A going into the plane of the figure while the outer region has a uniform current density of 1A m coming out of it A O B O TC R R The distance from the centre of the cable at which the magnetic field is zero is R O 3 1 2 R 1 R 2 C 1 O O

Which of the following is not an assumption of kinetic theory of gases The volume occupied by the molecules of the gas is negligible in comparison to the volume of the container O Intermolecular force of attraction repulsion between the molecules is negligible O All molecules of a gas move with equal speed O The collision between the molecules with the wall of container are elastic

Two circular discs A and B with equal radii are blackened They are heated to same temperatur identical conditions What inference do you draw from their cooling curves 1 A and B have same specific heats magifin haat of B is less R 20 A B 8 9 2 Specific heat of A is less 4 Nothing can be said RPMT 2007

Area of cross section of two rods of equal lengths are A and A and thermal conductivities are K and K Specific H are S and S condition for equal heat flow is 1 K K 2 K S K S 3 K K A S A S 4 K A K A

A spy satellite moves at a height of 50 km above the Earth s surface The minimum diameter of a telescope objective on board the satellite which can resolve objects separated by 2mm using a light of wavelength 600 nm is col A 18 3 m B 9 15 m C 18 3 cm D 9 15 cm

A 3 ha field was plowed using a 15 cm wide animal drawn plow at 4 kph and fie efficiency of 75 The draft required to pull the plow is 60 kg Find the distance traveled to plow the field a C 66 67 km 200 km b d 133 33 266 67 km

In a double slit experiment light of wavelength 750 nm and 900 nm illuminates the slits with a slit separation of 2 mm forming two fringe patterns The distance of the screen from the slits is 2 m At what distance from the central maximum on the screen will a bright fringe from one pattern coincide with the bright fringe from the other pattern A 1 5 mm B 3 75 mm C 4 5 mm D 6 0 mm

A diamagnetic object is hung by a thread from a very sensitive spring balance between the poles of an electromagnet When the magnetic field of the electromagnet is increased in magnitude the reading of the spring balance will S Spring balance sample N A slightly decrease B slightly increase C increase or decrease depending on the shape of the object D increase or decrease depending on the direction of the magnetic field bat

3 Become zero A beam of light composed of red and green rays is incident obliquely at a point on the face of a rectangular glass slab When coming out of the opposite parallel face the red and green rays emerge from AIPMT 2004 1 Two points propagating in two different non parallel directions 2 Two points propagating in two different parallel directions 3 One point propagating in two different directions 4 One point propagating in the same direction of ong kilometre from two objects

A conversing beam of rays is incident on a diverging lens Having passed though the lens the rays intersect at a por 15 cm from the lens on the opposite side If the lens is removed the point where the rays meets will move 5 cm clos to the lens The focal length of the lens is CAIPMT 20 1 10 cm 2 20 cm 3 30 cm 4 5 cm

and the emf of its standard cell is E volt It is employed to measure the emf of a battery whose internal resistance is 0 5 22 If the balance point is obtained at 30 cm from the positive end the emf of battery is 30 E 100 5 30 E 100 0 5 30 E 0 51 100 potentiometer wire 30 F 1 where i is the current in the

The magnetic field of Earth at the equator is approximately 40 x 10 Tesla If the Earth s magnetic field is due to a magnetic dipole at the centre of the Earth radius R 6400 km then the strength of the dipole is A 1023 Am B 102 Am C 10 Am D 1018 Am

Four identical point charges are placed at vertices of square ABCD of side 10 cm with centre at O A point charge placed on Z axis at point 0 0 d experiences maximum possible electrostatic force Value of d in cm is YA D A Answer 0 8 10 cm 0 8 C X B 1 2 3 4 5 6 7 9 1 2 3 3 4 5 6 7 9