Physics Questions

A block of mass 3m is connected with a string which is wound on pulley of mass m and radius R as shown in the figure If the system is released from rest Then acceleration of the block will be consider pulley as uniform disc x g 5g 3 3m

This question is from NEST 2020 ses sion 1 answer is there in similar quer ies but there it is given 2nd option w hereas here the answer is given as 4t h option pls verify Reply to the same question sent on Aug 12 2020 Q 5 A spherical bob hangs from a light inextensible string and moves in a horizontal circle with string making angle with the vertical The length of the string is then very slowly increased so that the motion is circular at all times to a good approximation If h is the height from center of the circle to the pivot and r is the radius of the circle then hor The value of a is X 3 X2 1 X 2 4 Ans 4

A pipe 30 cm long is open at both ends harmonic mode of the pipe resonates a 1 source will resonance with the same sou observed if one end of the pipe is clos Take the speed of sound in air as 330 1 4th Harmonic yes 2 II Harmonic yes 3 4th Harmonic No 4 II Harmonic No

If electron proton are 1A apart start m towards each other due to mutual attra Estimate acceleration of electron approxim 1 1 4 x 1019 m s2 2 2 5 x 1022 r 3 1 x 10 m s 4 2 3 x 10 8

instant of projection g 9 8m s 22 5 m 2 14 s 15 65m s 3 745 s From the top of a structure 100m high a body is projected vertically upwards with a velocity of 39 2m s Find a how high it will rise b velocity with which it strikes the ground and c time it takes to reach the ground g 9 8 m s 178 4 m 59 13 m s 10 03 s

From the top of a tower 102 9 m high a body is thrown upwards with a velocity of 19 6 m s How high will it rise and in what time How much time will it take to hit the ground Find the position and velocity of the body 5 s after projection g 9 8 m s no

46 In two dimensional motion instantaneous speed va is a positive constant Then which of the following is necessarily true 1 The average velocity is not zero at any time 2 Average acceleration must always vanish 3 Displacement in equal time intervals are equal 4 Equal path lengths are traversed in equal time intervals

7 If Gauss s law E ds 0 we can conclude 7 that 1 E must be zero 2 E must be perpendicular to surface 3 Total flux through the surface is zero 4 Flux is only going in the surface

In a metre bridge the null point is found at a distance of 20 cm from A If a resistance of 120 is connected in parallel with resistor S the null point occurs at 25 cm from A Find the value of R and S R A V S B

1 1 22 The position of a particle moving along x axis given by x 2 3t 5 m The acceleration of particle at the instant its velocity becomes zero is 1 12 m s 2 12 m s 3 6 m s 4 Zero

98 If the collector current changes from 2mA to 3 mA in a transistor when collector emitter voltage is increased from 2V to 10 V the output resistance is 1 1000 2 3 8 x 10 2 2 8000 2 4 500 52

m s A body is thrown vertically upwards with an initial velocity u How many times must the initial velocity be increased to secure double the height achieved in the first case If the body is to travel upwards for double the time how many times must the initial velocity be increased

You have two strings that you can use to connect three masses as you see in the diagram m 2kg m 1kg m 5kg They are placed on a frictionless surface String A can only bear a tension of 10N and String B can only bear a tension of 20N How do you arrange the two strings s that you can apply the maximum force and achieve the maximum acceleration What are the maximum force and the maximum acceleration

it takes to reach the ground g 9 8 m s 178 4 m 59 13 m s 10 03 s An object is thrown straight up with a speed of 30 m s How high above the point of release is it and what is its velocity after 1 2s 2 6 s How high does it rise g 9 8 m s 19 4 m s 40 4 m 28 8 m s 3 6 m 45 9 m

4 The path difference between two interfering waves at a point on the screen is from 6 central maximum The ratio of intensity at this point and that at the central fringe will be 2 8 53 4 0 853 1 0 75 3 7 5 CENTRA

88 De broglie wavelength of an electron movin with a velocity of 1 5 x 108 ms is equal t that of a photon The ratio of kinetic energy o the electron to that of the photon is 1 2 2 4 3 1 4 1

its around the sun with sun at with constant velocity ts around the sun with sun at one d maximum distances of a planet 9 10 4 None of these Force of gravitation between two masses is found to be F in vacuum If both the masses are dipped in water at same distance then new force will be 1 F 3 F 2 F 4 Cannot say Two point masses mand Am are separated by a

Paragraph for questions 24 27 A block of mass 15 kg is placed over a frictionless horizontal surface as shown in Fig 4 120 Another block of mass 10 kg is placed over it that is connected with a light string passing over tow pulleys fastened to the 15 kg block A force F 80 N is applied horizontally to the free end of the string Friction coefficient between two blocks is 0 6 The portion of the string between 10 kg block and upper pulley is horizontal Pulley string and connecting rods are massless take g 10 m s fam Smooth 10 kg 0 6 15 kg Figure 4 120 O F 80 N

35 If two sounds of very close frequencies 256 Hz 35 and 260 Hz reach our ear simultaneously then we hear a sound of frequency 1 258 Hz 2 4 Hz 4 None 62Hz

Unleashing Potential In the circuit shown in figure input source is periodic and its wave form is 18 Find the reading of cathode ray oscilloscope CRO is R www Sol 1 3 Ans 4 t 1 1 t t3 2 t4 CRO t Relide INSTITUTE 8

For a p n junction diode barrier potential Vo is shown for unbiased condition 321 Choose the correct statement among the following Both 2 and 3 represents forward biasing hr min Both 2 and 3 represents reverse biasing 2 represents forward biasing and 3 represents reverse biasing 3 represents reverse biasing and 1 represents forward biasing

JEE Advanced 2019 Two identical moving coil galvanometers have 10 resistance and full scale deflection at 2 A current One of them is converted into a voltmeter of 100 mV full scale reading and the other into an Ammeter of 1 mA full scale current using appropriate resistors These are then used to measure the voltage and current in the Ohm s law experiment with R 1000 22 resistor by using an ideal cell Which of the following statements s is are correct 1 The measured value of R will be 978 9 R982 Q 2 The resistance of the ammeter will be 0 02 2 round off to 2nd decimal place If the ideal cell is replaced by a cell having internal resistance of 5 2 then the measured value of R will be more than 1000 S 3 4 The resistance of the voltmeter will be

30 In a potentiometer of 10 wires the balance point for measuring the emf of a cell is obtained on 6th wire To shift the balance point on 8th wire we should 1 Decrease resistance in series with the cell whose emf is to be measured 2 Increase resistance in series with the cell whose emf is to be measured 3 Decrease resistance in main circuit in series with potentiometer battery 4 Increase resistance in main circuit in series with battery

If a EM wave traveling in vacuum in y direction has magnetic field B 8 10 k Then value of electric field E is 1 24 1 2 eliable INSTITUTE 2 24 i 3 2 6x10 16 1 4 2 6 10 6 1 Address Reliable Institute A 10 Road No 1 IPIA Kota 324005 Rajasthan INDIA visit us at www reliablekota com Email info reliablekota com Call us 91 744 2665544 11

9 What is the launch angle that will produce the maximum range of a projectile if there is no air resistance If there is air resistance will the angle be less than equal to or greater than the launch angle with no air resistance

Reliable INSTITUTE JEE MAIN MARCH 2021 DATE 16 03 2021 SHIFT I Unleashing Potential A planet is revolving around sun in elliptical orbit Maximum minimum distance of planet from sun are respectively 1 6 10 2 m and 6 100 m Find minimum speed if maximum speed of planet is 8 10 m s 1 3 x 10 m s 2 3 x 10 m s 3 ns 3 ol L m Vmax Imin m Vmin Imax 8 10 6 10 0 Vmin 1 6 10 2 X X 3 8 x 10 m s 4 4 x 10 m s

Two trains 200 m and 150 m long are running on parallel rails at the rate of 40 kmph and 45 kmph respectively If they are running in the same direction What distance the longer train moves during crossing

13 discharging graph In YDSE D 10 m d 1 mm and fringe width of interference pattern is 0 6 nm evaluate in nm 600 0 6 x 10 10xx 10 3 0 6 107 m 600 10 m 600 nm IMG 324005 ID i then INDIA

The potential energy of a 2 kg particle free to move along the x axis is given by V x J The total mechanical energ 2 of the particle is 2 J then the maximum speed in m s is

48 Read following statements carefully and mark the correct option Statement 1 With the displacement wave we can produce a pressure wave and Statement 2 Displacement and pressure wave both are having the phase difference T 2 1 Statement 1 is True Statement 2 is True Statement 2 is a correct explanation for Statement 1 2 Statement 1 is True Statement 2 is True Statement 2 is not a correct explanation for Statement 1 3 Statement 1 is True Statement 2 is False 4 Statement 1 is False Statement 2 is True

A particle undergoing rectilinear motion has its velocity vs distance travelled as shown below 1 3 s 3 Draw its acceleration vs distance graph 50 In interval 0 to 200m 15 V 10 10 200 400 5 INSTITUTE 6 Rejoble

Two logic circuits are shown in the figure A a BB The logic operation carried out by the two circuits are respectively A b NAND AND AND OR NAND NOR AND NOR X Y

A parallel plate capacitor with A wL is partially filled to a distance h with a material of dielectric constant K a What is its capacitance as a function of h b The internal capacitance has a charge Q find the potential energy as a function of h What if h 0 or h L c If F U h find the corresponding force

T Two perpendicular harmonic oscillations x a sin oot 2 y a sin at are superposed What will be the resultant motion y sin at T add af x asin at and

6 Calculate final velocity of the particle of mass 2kg if initial velocity of it is 6 m s A force if it is acted on it and whose variation with time has been shown below F N 10 m s 6 m s 12 m s t sec

8 A particle of mass m and charge q projected with a speed u at an angl e above the horizontal after travelling a horizontal distance xo enters region where in addition to gravity a uniform static horizontal electri field also exists Boundary of this region is vertical If after some time the particle returns to the point of projection find magnitude of th electric field and time of flight of the particle Acceleration of free fall g and influence of the air is to be neglected

xample 18 Three particles of masses m 2m and 3m are placed at the comers of an equilateral triangle of side a Calculate 0 0 The potential energy of the system The work done on the system if the side of the triangle is changed from a to 2a Assume the potential energy to be zem when the separation is infinity

34 A series LCR circuit is connected to an ac source of variable frequency When the frequency is increased continuously starting from very small value the power factor 1 Goes on increasing continuously 2 Goes on decreasing continuously Remains constant Q s R Z

Consider a parallel plate capacitor for which the plates are separated by a vertical distance 2d Suppose that the space between the plates is filled with two slabs of linear dielectrics each of thickness d The upper slab has dielectric constant 3 and the lower slab has dielectric constant 2 If the free charge density on the upper and lower plate is o and respectively calculate for each slab a the electric displacement b the electric field c the polarization d the location and value of the bound charges

The output of the given circuit in figure shown R www V Will be zero for all time Is Half wave rectified with Positive cycle in output Is Half wave rectified with negative cycle in output Is full wave rectified

The displacement of the wave given equation y x t asin kx ot wh p 0 at point x and t 0 is same as that at poi 1 x 2n 3 kx 2n 2 x 2nt k 4 None

3 10 The wavelength of a standing wave in a 40 cm The phase difference between two particles separated by distance 10 cm will be 240 1 Zero 3 T 2 EN 2 4 Either 0 or

A particle of mass rotates in a circle which has a vertical boundary of radius 0 2 meter rotating in horizontal plane Mass of the block is 200 gram It takes 40 second in one complete revolution Find the normal force on block 1 9 8 10 N 2 9 8 10 2N 1 N mo R 2 0 2 47 R 0 2 4 9 8 1600 9 8 10 N 0 2 3 9 8 N 4 9 8 10 N INSTI

If you weigh 655 N on the earth what would be your weight on the surface of a neutron star that has the same mass as our sun and a diameter of 19 0 km Take the mass of the sun to be m 1 99x1030 kg the gravitational constant to be G 6 67 10 11 Nm kg2 and the free fall acceleration at the earth s surface to be g 9 8 m s Express your weight War in newtons View Available Hint s Wstar VAE 1 2210 4 Patty N

O Single Correct MCQ A student measured the length of a rod and wrote it as 3 50 cm Which instrument did he use to measure it A B C D A screw gauge having 100 divisions in the circular scale and pitch as 1 mm A screw gauge having 50 divisions in the circular scale and pitch as 1 mm A meter scale A vernier calliper where the 10 divisions in vernier scale matches with 9 division in main scale and main scale

The mass of a pigeon hawk is twice that of the pigeons it hunts Suppose a pigeon is gliding north at a speed of Up 24 2 m s when a hawk swoops down grabs the pigeon and flies off as shown in the figure The hawk was flying north at a speed of VH 34 6 m s at an angle 0 45 below the horizontal at the instant of the attack What is the birds final speed uf just after the attack Uf m s What is the angle of below the horizontal of the final velocity vector of the birds just after the attack 0 Hawk o VH up Pigeon north Up

The transfer characteristics between V and V for CE transistor is shown in the figure KL V The region in which transistor acts as a switch ON is Roth Land III

wind turbine has 12 000 kg blades that are 9 m long The bladen spin at 23 rpm Part A If we model a blade as a point mass at the midpoint of the blade what is the inwe force necessary to provide each blade s centripetal acceleration Express your answer with the appropriate units F 1 29 106 Submit N

A bullet of mass m embeds itself into a larger block of mass M If the maximum angle that the bullet block system rises after the collision is 60 the length of the string is 1 m and the velocity of the bullet before the collision is 4 142 m s find the energy loss during the collision Assume the bullet has a mass of 1 gram and the block has a mass of 1 kg Use g 10 m s Express answer to three decimal places OH M M m 1 0

In photoelectric experiment both sodium work function 2 3 eV and tungsten work functio 4 5 eV were illuminated by an ultraviolet light of same wavelength If the stopping potent of tungsten is measured to be 1 8 V the value of the stopping potential for sodium will be A 4 V B 4 2 V C D 3 4 V 4 3 V