Physics Questions

Express the following gains as a number Power gain of 40 db Note Write complete number Do not put decimal e g if answer is 20 40 then write it as 20 and if answer is 20 60 then write it as 21

are told a certain object has a temperature of 497 K What is this objects temperature in egrees Celsius and Degrees Fahrenheit 497K 273 224 9 497 32 926 Gf 5 Fahrenheit reworked 497 273 49 32 435 2 F 5 32 S Bonus Addendum to problem 21 5 bonus pts There is another temperature scale called Rankine This scale has units the same size as degrees

A man mass 50 kg and his son mass 20 kg are standing on a frictionless surface facing each other The man pushes his son so that he starts moving at a speed of 0 70 ms 1 with respect to the man The speed of the man with respect to the surface is

A vertical ring of radius r is made of a uniform wire of resistance R It slips vertically between two frictionless and resistanceless vertical rails There is a uniform magnetic field B perpendicular to plane of ring and rails as shown in figure When the speed of ring is v then the current in section PQ at that NBvr 2R Value of N is instant is XXXX X X X X X X XXXX X X X X

5 Find the expression for the torque experienced by an electric dipole placed in a uniform electric field Question 16 Find the expression for the potential energy of a system comprising of three point charges q q and 93 placed respectively at the three vertices of an equilateral triangle having length r OR

gement shows two long metallic rails connected to resistance R forming an inclined plane Magnetic field is vertical in the region If slider of mass m and length will move with the terminal am NmgR sin 0 velocity incline is smooth B cos e then value 0 of Nis R www 0 l m B 0

Two infinitely charge sheets having charge density and 20 as shown in the figure The electric field at the point P will be G 20 O 280 30 280 View in y a

English Two very small spheres having charge Q and Q face each other at a certain distance between them If a dielectric having dielectric constant Kinserted between them then electrostatic force between them O Increase O Decrease O Remains same Becomes zero View in

An object of mass 0 2 kg is hung from a spring whose spring constant is 80 N m The object is subject to a resistive force given by bu where v is its velocity in meters per second a Set up the differential equation of motion for free oscillations of the system b If the damped frequency is 3 2 of the undamped frequency what is the value of the constant b

Determine the output f for the logic circuit shown below Minimize the output f function using Boolean algebra and sketch the minimized logic circuit D XO YO ZO Do Output

The mutual induction between primary an secondary coils of a transformer is 2 H If an A current of peak value 5 A and frequency 50 H flows through the primary coil then the pea voltage in secondary coil is 2 10 volts 4 20 volts 1 10 volts 3 1000 volts

What is the force between two small charged spheres carrying charges 3 x 10 C and 4 x 10 C placed 40 cm apart in air Question 4 2

A beam of light is passed through a polariser and an analyser The latter is then set for maximum inten sity of transmission To reduce the intensity to 1 fraction one tries four ways of turning the analyser A and polariser P 1 A 20 P 40 2 A 75 P 15 4 A 0 P 60 3 A 60 P 0 Here and stand for clockwise and anti clockwise turning Which one will work

19 Consider a plastic cube that has an edge dimension of 20 0 cm and a density of 0 400 g cm placed in a fluid of the density 0 800 g cm What force magnitude and direction is required to keep this cube completely submerged in the fluid

A coil of inductance L 2 0 uH and resistance R 1 Q2 is connected to an ideal source of constant rolini emf 3 V as shown in the figure The amount of E heat in J produced in the coil after the switch S is disconnected is qe is O n doel hi L R 10000 www R 22 S dalar HH 3 V AV er gain to

3 Find the expression for the electric field intensity at a point distance r apart from a charged spherica conductor Question 13

Find the expression for the electric field intensity at the broad side on position of an electric dipole OR Find the expression for the electric field intensity at the end on position of an electric dipole Question 14

Two parallel plates are of potential 20 V and 40 V If the separation between them is 4 cm The electric field between them is O 500 V m O 1000 V m O 2000 V m View in 1500 V m

A gun is placed on smooth horizontal surface fires a bullet of mass 200 g at a speed of 10 m s relative to the barrel of gun which is inclined at angle of 60 from horizontal The gun is one kg mass By what velocity the gun rebounds backwards

A comb run through one s dry hair attracts small bits of paper This is due to O Comb is a good conductor O Paper is good conductor O The atom in the paper get polarised by the charge comb The comb possesses magnetic properties

Q The magnitude of the force in Newtons acting on a body varies with time t in microseconds as shown in fig AB BC and CD are straight line segments The magnitude of the total impulse of the force on the body from t 4 us to t 16 us is N s A B C D 5 x 104 N s 5 x 10 3 N s 5 x 10 5 N S 5 x 10 2 N s Force F N 800 600 400 200 O A 2 B F IE 6 Time us 8 00 10 12 14 D 16

Joining q7 and 9 Question 17 Find the expression for the equivalent capacitance of three capacitors having respective capacitances C and C3 connected in parallel OR

A satellite is launched and attains a velocity of 30400 km hr relative to the centre of the earth at a height of 320km from the earth s surface It has been guided into a path that is parallel to the earth s surface at burnout Choose the correct options a Satellite moves along an elliptical orbit b Longest distance from the earth s surface is 3550 km The period of revolution for the satellite is 2 09 brs

A charge Q is enclosed by a Gaussian spherical surface of radius R If charge and radius of Gaussian surface is doubled then outward electric flux will Becomes four times Remains same Becomes doubled Becomes half View in English

Sutingsm 30 Solve the following Certain stars are believed to be rotating at about 1 rot s If such a star has a diameter of 40 km what is the linear speed of a point on the equator of the star domoso 2 marks

tensity at the end on position of an electric dipole Question 14 3 A charged oil drop weighing 1 6 x 10 5 N is found to remain suspended in a uniform electric field of intensity 2 x 10 N C Find the charge on the drop Question 15 Find the expression for the torque experienced by an electric dinole placed in a uniform electric figold 3

Two rings each of radius a are coaxial and the distance between their centres is a The masses of the rings are M and M The work done in transporting a particle of a small mass m from centre C to C is Gm M M a

Give your answer in Joule Question 9 3 The electric field intensity at a point distance 20 cm apart from an infinite line of charge of is 5 N m Find its linear charge density Question 10 Find the expruction 3

0 i A block of mass 3 kg is pushed against a rough vertical wall of friction coefficient 0 5 by a force F applied at an angle 45 with the vertical and 45 with the normal to the wall Find a the minimum value of F for which the block will remain in equilibrium b the acceleration of the block if the force applied is 2 Fmin found in part a ii If the direction of F can be changed find the minimum value of F required to keep the block at rest by pressing it against the wall

The potential on the surface of hollow sphere of radius 2 m is 200 volt The potential at 1 m from the centre of the sphere is O 100 volt O 200 volt O 400 volt View in Zero

The magnitude of electric force experienced by a charged particle in an electric field depends o O Charge of the particle O Velocity of the particle O Direction of electric field O Mass of the particle

A universal motor ac operated has a 2 pole armature with 960 conductors At a certain load the motor speed is 5000 rpm and the armature current is 4 6 A the armature terminal voltage and input are respectively 100 V and 300 W Compute the following assuming an armature resistance of 3 5 2 a Effective armature reactance b Maximum value of useful flux pole

9 Two similar rods of length 1 and I each of iron and b respectivel expansion of iron and brass are a and raised then determine the relation 1 1 A Oa a a B Oa a a C Oa a ap D O aa

Which of the following statement is incorrect Moment of inertia is independent of distribution of mass about rotational axis Moment of inertia depends on orientation and position of axis of rotation Moment of inertia is independent of angular velocity of rotating body Flywheel resists sudden increase or decrease of speed of vehicle

A car drives around a circular track of diameter 128 m at a constant speed of 38 1 m s During the time it takes the car to travel 168 degrees around what is the magnitude of the car s average acceleration

Q 1 A car travelled a distance of 900 km It developed an engine problem after travelling for some distance It travelled the remaining distance at 3 5th of its speed It reached 2 hours late If the engine problem had developed after it had travelled for another 150 km it would have reached 1 hour earlier that the time it actually reached Find the distance it travelled without any problem in km Marks 2 500 400 600 700 None of these

An ideal incomplete expansion cycle uses steam generated at 1 85 MPa The release condition is dry and saturated Exhaust steam is at 0 03 MPa and has 10 58 quality The actual engine uses 1000 kg h of steam The brake engine efficiency is 60 and the mechanical efficiency is 85 a For the ideal engine calculate the thermal efficiency and MEP For the actual engine calculate b the brake power in kW and the brake thermal efficiency c the indicated thermal efficiency and the indicated heat rate d the approximate enthalpy of the exhaust steam at 0 03 MPa assuming that the heat loss from the engine is 23 kJ per kg of steam

The reaction time is the time interval in which a person Observes the incident Think about the observations Takes the action

At a certain distance from a point charge in C the electric field is 200 V m and the potential is 800 V What is this distance O 8 m O 4m O 2 m 16 m View in

A ring of radius r has given a charge Q and uniformly distributed over its length If a charge q is placed at the centre The electric potential energy of the charge q will be kqQ kqQ r kg Q r

English Four charges 1 C 2 C 3 C and 4 uC are placed at 1 m 2 m 3 m and 4 m from origin The net electric potential at the origin will be O 9 KV O 18 KV 36 kV Zero View in

In the LC circuit at this time Q Q 00000 1 is increasing and Q is increasing 2 is increasing and Q is decreasing 3 is decreasing and Q is increasing and deprem

A cylinder contains SO2 gas at a pressure of 4 1 atmosphere and at 47 C temperature The density of the gas in the cylinder is 0 2 g ml 0 4 g ml 0 01 g ml 10 g ml

An electric pump on the ground floor of a building takes 10 minute to fill a tank of 45 m with water The tank is 20 m above the water level If electric power consumed by the pump is 30 kW then efficiency of the pump will be density of water is 1000 kg m 33 75 50

When energy of a satellite Earth system is non zero positive then satellite w Move around the earth in circular orbit Just escape out Move around the earth in elliptical orbit

Q A liquid drop of radius R is broken into n identical smaller drops of radius r Find i increase in surface energy ii decrease in temperature of liquid assume increase in surface energy comes from thermal energy of liquid Given T Surface Tension p density of liquid S specific heat capacity of liquid

3 A massive sphere is fitted onto a light rod at a distance x from ground end and it is placed vertically Assume the end of rod on the ground does not slip for which of the following values of x the rod will fall faster if A X B x 2 C x 14 D rate of falling of rod is indpendent of x

View in The charge to be put on a spherical conductor of radius 0 2 m to produce an electric field of 0 072 N C just above its surface is O 16 10 14C O 8 10 14C O 32 10 14C

Two concentric uniformly charged spheres of radius 10 cm 20 cm are arranged as shown in the figure Potential difference between the spheres is 1 4 5 x 1011 V 2 2 7 x 1011 V 3 O 4 none of these 10C 10cm 20cm 20C

If the electric potential of the inner shell is 10 volt that of the outer shell is 5 volt then the potential at the centre will be the shells are uniformly charged 1 10 volt 3 15 volt 2 5 volt 4 0 a