Basic Physics Questions and Answers

Vhen viewed in sunlight a flower has red petals and a green stalk You pluck the flower and take it to a rom luminated with a red lamp What colours does the flower now appear to be Black petals and green stalk D Black petals and a black stalk 2 Red petals and a black stalk Red petals and a green stalk

0 4 D 0 2 50 100 150 Temperature T K FIGURE 3 9 esistivity p of er as a function emperature T For listed in Table 3 1 rang would be a straight line At temperatures much lower than 0 C the grap The relation of Eq 3 26 implies that a graph of p plotted against however deviates considerably from a straight line Fig 3 9 Equation 3 26 thus can be used approximately over a limited r of T around any reference temperature To where the graph can approximated as a straight line IMP Resistivity pufcm 1 20 1 10 1 00 200 400 600 800 Temperature T K FIGURE 3 10 Resistivity Pr of nichrome as a function of absolute temperature T P IMP T FIGURE 3 11 Temperature dependen of resistivity for a typic semiconductor

ontal edge orizontally the axis of ne vertical at friction nt causes ermine 5 53 In the arrangement shown in figure 5 153 a weight A possesses mass m a pulley B possesses mass M Also known are the moment of inertia I of the pulley relative to its axis and the radii of the pulley R and 2 R The mass of the threads is negligible Find the acceleration of the weight A after the system is set free Ans 3 M 3m g I M 9m 2 R 2R A Figure 5 153 B The F any p and t Ans 5 58 and two as Cal str str An

When viewed in sunlight a flower has red petals and a green stalk You pluck the flower and take it to a ro lluminated with a red lamp What colours does the flower now appear to be 1 Black petals and green stalk b Black petals and a black stalk c Red petals and a black stalk d Red petals and a green stalk

Determine the forces in each member of the truss shown below State whether each member is in tension or compression Also calculate the support reactions at A and H Show all the steps and calculations 1 kip 1000 lb 6 kips A BV C 9 ft 9 ft D E 9 ft 6 kips 6 kips VF G 12 ft

3 With O as the origin of the coordinate axis the X and Y coordinates of the centre of mass of the system of particles shown in the figure may be given as Here m and 2m represent the masses of the particles X m 2m Hb b b M 18 19 X mxbt 2 mxbt m 6m 4mx5b12 mx 20 6 m 6m x 122

nown in figure 5 150 alculate the linear What is the minimum event slipping 5 Nt adius R rotates 5 46 A uniform rod AB of mass 2 kg and length 100 cm is placed on a sharp support O such that AO a 40 cm and OB b 60 cm A spring of force constant k 600 N m is attached to end B as shown in figure 5 151 To keep the rod horizontal its end A is tied with a thread such that the spring is elongated by y 1 cm Calculate the reaction of support on the rod when the thread is burnt O Ang 120 N a T Figure 5 151 eeeeeeee STORY

The primary winding of an ideal transformer has 1000 turns whereas its secondary has 5000 turns The primary is connected to an ac supply of 220 V 50 Hz The secondary will have an output of 550 V 1100 V 440 V 44 V

A motorized wheel is spinning with a rotational 01 0 1 17 rad s Al s the higher speed setting The rotational velocity of the wheel at all subsequent times is given by w t woarctan c bt where c 1 5574 and b 6 53 s At what time tamax is the rotational acceleration at a maximum tamax 0 533 Incorrect erator switches the wheel to a What is the maximum tangential acceleration a of a point on the wheel a distance R 1 21 m from its center

Q12 An 11 0 4 kV 25Hz single phase transformer has ohmic hysteresis and eddy current losses of 1 8 0 8 and 0 3 respectively What do these losses become if transformer is operated from 22kV 50Hz supply system The current is assumed to be same in both the cases Also calculate efficiency in each case

49 Two stationary sources each emit waves of wavelength 2 An observer moves from one source to another with velocity u Then number of beats heard by him 1 2u 2 2 3R 2

3 The average speed for the first 4 s is zero 4 The average velocity for entire journey is 5 m s 7 The position of a body moving along x axis at Q 47 taria y time t is given by x 21 10t 5 metre The 21 10t 5 e distance travelled by body between t 1 5 s to t 3 sis 1 7 m 3 5 m 3 4 4 fare sterer 5 m s 2 5 5 m 4 2 5 m frufe x t 1 5 st 3s 1 7 m 3 5 m 2 5 5 m 4 2 5 m 1

A transistor is used in common emitter mode in an amplifier circuit When a signal of 20 mV is added to the base emitter voltage the base current changes by 20 A and collector current changes by 2 mA The load resistance is 5 kQ The transconductance of the amplifier and voltage gain is respectively 0 1 mho 500 0 1 mho 50 0 2 mho 500 0 2 mho 50

The bob of a swinging seconds pendulum one whose time period is 2 s has a small speed vo at its lowest point Its height from this lowest point 2 25 s after passing through it is given by 7 VO 2p B vo g C D ovo 4g

24 4 59 Block B of mass 100 kg rests on a rough surface of friction coefficient u 1 3 A rope is tied to block B as shown in figure The maximum acceleration with which boy A of 25 kg can climbs on rope without making block move is 4g B 201 m 100kg B u 1 3 37 C A 25kg D 3g

At temperature 23 C the resistance of a wire is 100 Q The temperature at which resistance becomes 104 Q i nearly Given temperature coefficient of resistance of material is 1 5 10 4 C O 1027 C 827 C O 290 C O 290 K

ing Initial conditions have been set up so that a coin of radius r rolls around in a circle as shown in Fig 9 54 The contact point on the ground traces out a circle of radius R and the coin makes a constant angle with the horizontal The coin rolls without slipping assume that the friction with the ground is as large as needed What is the frequency 2 of the circular motion of the contact point on the ground Show that such motion exists only if R 5 6 r cos 0 Fig 9 54

A plane mirror is moving with velocity 42 53 8k A point object in front of the mirror moves with a velocity 31 41 5k here k is along the normal to the plane mirror and facing towards the object The velocity of the image is

An acoustic engineer places a sound detector on a railway station A train approaching the platform at a speed of 10 m s sounds a whistle The detector detects 10 kHz as the most dominant frequency in the whistle If the train stops at platform and sounds the whistle then most dominant frequency detected will be nearly Vsound 340 m s 9 7 kHz 11 3 kHz 10 3 kHZ

47 Two simple pendulums of length 1 m each with bobs having masses 1 kg and 2 kg are hanging from the ceiling of an elevator The elevator starts moving vertically downwards with acceleration g 10 Assuming g 10 m s approximately what are the time periods of the two pendulums A 2 1 s and 3 0 s B2 1s and 2 1 1 9 s and 2 7 s D 1 9 s and 1 98

m Two planets have masses M and 16 M and their radii are a and 2a respectively The separation between the centres of the planets is 10a A body of mass m is fired from the surface of the larger planet towards the smaller planet along the line joining their centres For the body to be able to reach the surface of smaller planet the minimum firing speed needed is GM GM GM2 3 5GM

ar d e 1 48 A stone is thrown from ground level so as to just clear a wall 4 m high at a distance of 4 m and falls at a distance of 14 m from the wall Find the magnitude and direction of the velocity of the ball Ans 182 m s

nal ha 4 68 Find the mass of the rocket as a function of time it moves with a constant acceleration a in absence of external forces The gas escapes with a constant velocity u relative to the rocket and its mass initially was mo Ans m me me falu

6 A plank of mass 10 kg is kept on a rough horizontal surface A block of mass 2 kg is kept over the plank The coefficient of friction for the surface in contact is given A force of magnitude 66 N is applied horizontal as shown in the figure Calculate the work done by the friction on the upper block in 5 sec Assume the plank is long enough A 100 J M 0 2 H 0 1 77 B 100 J 2 kg 10 kg C 200 J F D Zero

2 30 A small body was launched up an inclined plane set at an angle a against the horizontal Find the coefficient of friction if the time of the ascent of the body is n times less than the time of its descent Ans k n 1 n 1 tana

3 Is 3m point group symmetry equivalent to 3mm Clarify 4 In an orthorhombic crystal system body centered face centered and end centered lattices are possible but why are all these types of centered lattices not possible in tetragonal crystal systems Explain using figures

377 47 A standing wave having 3 nodes and 2 antinodes is formed between two atoms having a distance 1 21 between them The wavelength of the standing wave is 1 6 05 2 2 42 3 1 21 A 4 3 63 4

Two parallel rays incident on the combination of two lenses A and B placed in close contact as shown below Then choose the correct option among the following AB a Both A and B can be concave lens b Both A and B can be convex lens c A can be convex and B can be concave but power of B must be greater than power of A d A can be concave and B can be convex but power of B must be greater than power of A

A parabolic section is located in x y plane and carries a current of 12 A A uniform magnetic field B 0 4 T making an angle of 60 with x axis exits throughout the plane What is total force on wire between origin and point x 0 25 m y 1 00 m X X P 1 36k N O 2 4KN O 1 72K N O 1 42 K N 60 B B A

Find the acceleration in m s2 of the 6 Kg block in the figure All the surfaces and pulleys are smooth Also the strings are inextensible and light Take g 10 m s 2kg 2kg 30 6kg

2 kg ice at 20 C is mixed with 5 kg water at 20 C Then final amount of water in the mixture will be Specific heat of ice 0 5 cal gm C Specific heat of water 1 cal gm C Latent heat of fusion of ice 80 cal gm 6 kg 7 kg 3 5 kg

Medium 1 4 2 and medium 2 1 25 are separated by a cylindrical interface of ROC R A plane mirror is placed in medium 2 at angle as shown in figure Find value of 0 in degrees such that a light ray parallel to principal axis incident from medium 1 at height R 2 retraces its path after reflection from the mirror PA 1 TRI 2 M O H e

miles away on the ground the rate of change of elevation of balloon is 0 1 rad min What is the rate of change of its vertical height from the ground when angle of elevation is SolveLancer Test a 1 miles min b 2 miles min c 2 5 miles min d 3 miles min O a D b CO

If a particle is moving on a circular path with constant speed then the angle between the direction of accelerati and its position vector w r t centre of circle will be 1 Zero 3 T 2 4 E N 2 2TT

Tia s house and Rimi s house are connected by a 1000 m long straight road One day Tia starts walking from her house towards Rimi s When she had walked 150 m Rimi starts walking from her house towards Tia s If they walk at the same speed how far will they be from Rimi s house when they meet a 700 m b 425 m c 350 m d 150 m

x A long solenoid of cross sectional radius a has a thin insulated wire ring tightly put on its winding one half of the ring has the resistance n times that of the other half The magnetic induction produced by the solenoid varies with time as B bt where b is a constant Find the magnitude of the electric field strength in the ring ab n 2 m 1

A rectangular loop PQRS made from a uniform wire has length a width b and mass m It is free to rotate about the arm PQ which remains hinged ZA along a horizontal line taken as the Y axis see figure Take the XI vertically upward direction as the Z axis A uniform magnetic field B 3 4k B exists in the region The loop is held in the X Y plane and a current I is passed through it The loop is now released and is found to stay in the horizontal position in equilibrium Then a the direction of current in PQ is form P to Q b magnetic force on arm RS is IBob 3k 4 mg c I 6B b 2mg 7B h d I S P Q R Y

The rate of Production of a resource is related to the demand and Supply as df f D f s where P ix cumulative production of the resoured the the time fCD and f s are the functions of clemand and supply respectively If U be the ultimate amount of reforce then I be the fraction that has been produced and 1 1 is the fraction remaining If a I a f D ff and f s 1 1 P then show that 1 exp C u km where C is constant of proportionality and to be the time at which Plot rate of production with time for different values of U the production rate peaks

Marks 4 0 An electric field E 101 20j N C exists in the space If the potential at the origin is taken to be zero find the magnitude of potential in V at 3m 3m

2 If a vessel containing a fluid of density p upto height F is accelerated vertically downwards with acceleration ao Then the pressure by fluid at the bottom o vessel is a p Po pgh phao b p Po pgh c p Po ph g ao d p po pgh

The following statements S and S are observed S Conductivity of HCl increases with dilution S Molar conductivity of HCI increases with decrease in concentration The correct option among the following is A 5 is wrong and S is correctAY B Both S and S are wrong C s is correct and S is wrong D Both S and S are correct

1 2 3 2 Width of a slab is 6 cm whose from the front face Calculate the final position of the image from the silvered surface If its rear surface is silvered and object is placed at a distance 28 A light ray is moving from dongo

The I V characteristics for two semiconductor devices a shown in figure A V Volt A a The corresponding devices are LED Solar cell LED Photodiode Photodiode Solar cell b V

Marks 4 0 0 A uniform slab of dimension 10cm x 10cm x 1c is kept between two heat reservoirs at temperatures 10 C and 90 C The larger surfac areas touch the reservoirs The thermal conductivity of the material is 0 80 W m C Find the amount of heat in J flowing throug the slab per second

1 Show that 2m point group symmetry is equivalent to 2mm 2 The adjoining figure shows the tetrahedral disposition of covalent bonds in the diamond structure Realizing that the lattice constant for this structure is 3 56 A Calculate the length of a bond and the angle between any two bonds

EET PHYSICS All India Major Test Series Phase II Major Test 45 39 10 09 2020 154 A particle executes linear simple harmonic Q 154 fra 1344 32 cm motion with an amplitude of 3 cm When the particle is at 2 cm from the mean position the magnitude of its velocity is equal to that of its acceleration Then its time period in seconds is 5 7 4x 3 TE 1 2 4 5 2x 2 3 FERRER SA 8 5 2 4 5 2n 2r 3

1 8 01 2 eter wire is l A cell of length 1 4 from the me length of the wire is istance will the same bint Potentiometer 3100 IN 3l 8 l 527 C 127 C 2 50 Water has been filled in a vertical capillary tube upto the top after closing its lower end by a finger Consider radius of capillary r 1 mm surface tension is 70 dyne cm and g 980 cm sec Which of the option is correct when finger is removed 1 Whole of water will fall down from the capillary tube 2 Whole of water will stay inside the capillary tube 3 Nearly 1 42 cm of water will stay inside capillary tube and rest will fall down 4 Nearly 2 86 cm of water will stay inside the capillary tube and rest will fall down d 21500 GM 91

A statistician modeled the average private law school tuition in two ways According to both models the tuition in 2011 was about 40 000 In one model the tuition increased by 1750 per year In the other the tuition increased by 5 per year What would be the difference between these models in the year 2013

If for a man travelling up along a fixed inclin e of inclination 37 degrees at a speed of 10 m s the rain appears to be falling vertically downwards at 5 m s determine the actual s peed of the rain and the angle it makes with the horizontal and with the incline

following circuit If the applied voltage is increased from 2 V to 4 V then 2V HIF D Junction Diode R mA a the p d across the resistance R decreases b the p d across the diode increases c the p d across the diode remains constant