PHYSICS @ Viresh_iitk /test-2-JEE-2012

8/3/2019 PHYSICS @ Viresh_iitk /test-2-JEE-2012

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Test-6 / IIT-JEE / PHYSICS

Section -1 ( straight objective type )

1- The pressure and absolute temperature of an ideal gas is changing as shown inthe graph in certain thermal process. Choose the correct statement:

(a) Volume at states A and B are same(b) Volume at states A is more than that at B .

(c) Volume at states A is lesser than that of at B .(d) The process is isochoric.

2-There are three solid balls A,B and C , made ofsame material , have volumes in ratio 1 : 2 : 3 andtheir temperatures are T1 ,T2 and T3 respectively. After the balls A and B are placed in contact and oncethey attain thermal equilibrium, the ball A is touched with C and then the final temperature of A is foundas T3. The T3 equals

(a) T1 +2T2 (b) (T1 +2T2)/9 (c) (T1 +2T2)/3 (d) (2T1 +3T2)/5

3- The wave function of the sounds from the two sources are are 4 sin( 100 t) and 6 cos( 110 t)respectively. The resulting sound of the two sources changes its intensity with time. How many times,the resultant intensity of the two sounds, passes from its maximum value per unit time?

(a) 20 (b) 5 (c) 10 (d) 105

4- The coefficient of volume expansion of mercury is 20 times coefficient of linear expansion ofglass. The volume of mercury, that must be poured in to glass vessel so that the volume of space,in glass vessel above mercury , at all temperature remains constant, is

(a) one third of part of vessel (b) 3 /20 part of vessel(c)1/20 part of vessel (d) 7/20 part of vessel.

C5- Two rods X and Y are A Beach of length L and linear

expansion coefficient of their material are .Their outer ends are hinged at A and B and they are

touching each other at their junction C . If temperature of both rods is increased by t thenjunction C will move by nearly

(a) L (2 t )0.5 (b) L ( t )0.5 (c) L(2 t ) (d) L t

6-Sound sources A and B , when sounded together , produces 5 beats per second. When frequencyof source A is increased by 0.5 %, only 3 beats are recorded per second. The frequency ofsource B is

(a) 400 Hz (b) 402 Hz (c) 200 Hz (d) 405 Hz

7- A transverse stationary wave with wave function : a0cos ( 4 x ) sin ( 20 t+ 2 /3 ), isformed on a stretched string . Here time t is in seconds. How many times per second , stringbecomes straight?

(a) 10 (b) 20 (c) 40 (d) never

8- There are two thin spherical hallow boxes A and B having same thickness but their mean radiiare in ratio 2: 3. Both contain ice at 00 C. Both are kept in same surroundings. In certain timeinterval mass of ice melted in the box A is double of the mass of ice melted in the box B in sametime interval. Thermal conductivity of A and B will be in ratio

(a) 4:9 (b) 9:4 (c) 9:2 (d) 2:9

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9- When a rod X of length L is connected between an ice chunk and a heat source of fixed

temperature, m1 gram of ice melts each second, but if another rod Y of same length L is connected

between the same heat source and ice chunk, m1 gram of ice melts each second. Now the two rods are

joined to form a rod of length 2 L, and again they are connected between the same heat source and the

ice chunk.

Let the fixed temperature of the heat source is t0and ice temperature is 0 and the rod y is in contact of

ice and rod x is contact of the heat source. neglect the heat capacities of the rods. The temperature at the

junction of the two rods will be

(a) t0 m1 / m2 (b) t0 m2 / m1 (c) t0 m1 / (m1 + m2) (d) t0 m2 / (m1 + m2)

SECTION-2 ( Assertion & Reason type )

In this section four questions are given and each question is followed by two statements. Inthe answer sheet, mark(a) ifboth the statements are true and statement 2 is correct explanation of the statement 1(b) ifboth the statements are true but statement 2 is not correct explanation of thestatement 1(c) if the statement 1 is true but the statement 2 false(d) if the statement 1 is false but the statement 2 is true.

10-Statement 1 :When ice melts , its internal energy remains constantbecauseStatement 2 : During phase change, temperature does not change.

11- Statement 1 : In isothermal expansion of an ideal gas, heat absorbed is same as the work doneby the gas.

becauseStatement 2 : Internal energy of the ideal gases is directly proportional to the absolute temperatureand independent of volume.

12- Statement 1 : Under the effect ofstationary wave, all medium particles remain at rest.because

Statement 2 : In stationary wave all medium particles passes from the mean position simultaneously.

13- Statement 1: If two solid spheres ofdifferent size, made of same material and similar surfaceconditions ,with the same temperature are placed in same surroundings then the bigger one cools faster.because

Statement 2 : cooling rate is proportional to surface area but inversely proportional to the heatcapacity.

SECTION-3 ( Linked Comprehension Type )This section contains two paragraphs P14-16 and P17-19 .Each paragraph is followed by 3 questions withtheir multiple options for their answers. Choose the only one options which is most correct.

P14-16 : Paragraph for the Q. No 14 to 16

A rigid wall is placed at x =L. A longitudinal wave propagatingin positive x- direction is incident normally on the wall. Thedisplacement of the medium particles due to the incident wave isgiven by the wave function y = a cos ( b x c t ) where a, b and c are

positive constants. The air present in the space near the wall is ofmean density .14-The incident wave produces maximum pressure change in the air by amount

(a) a c2 / b (b) b c2 / a (c) a2 c / b (d) none of these

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15- If the wall reflects the sound completely i.e. no loss of sound energy, then the displacement of themedium particles near the wall , due to the reflected wave by the wall only, will change with time t as

(a) a cos ( b L c t ) (b) a cos ( b L+ c t + ) (c) a cos ( b L + c t ) (d) a cos ( b L- c t + )16- Under the combined effect of the incident wave and reflected wave , the air molecules at somepositions are found always at rest. The x- coordinate of one of such point which is nearest to the wallbut not at the wall) is

(a) L 0.5 / b (b) L - L 0.25 / b (c) L / b (d) L 2 / b

P17-19 : Paragraph for the Q. No 17 to 19A non conducting vessel with uniform cross section , is closed at both ends and has volume4V0. A frictionless conducting piston which just fits in the cylinder separates the vessel initiallyin two parts of equal volume 2V0 each ,containing ideal gas of same nature in both side. Initialpressure on both sides of the piston is p0 but initial temperature on left side is T0 and on theright side of piston is 3T0.

17- After long time temperature on both side of the piston is found to be same. This commontemperature will be

(a) 2T0 (b) 3T0 / 2 (c) 2T0 / 3 (d) none of these

18- After the long time volume of the left side of the piston will be

(a) 3 V0 (b) 2 V0 (c) 3 V0/2 (d) none of these19- If the piston would have been fixed, then final temprature on both side of the piston would have been(a) 2T0 (b) 3T0 / 2 (c) 2T0 / 3 (d) none of these

SECTION-4 ( Matrix- Match Type )20-An ideal gas may under go any thermal process as given in the following column II and somestatements are given in the column I . Match the items in the column I with the correct descriptionsgiven in the column II and indicate your answer by darkening appropriate bubbles in the 4 x 4 matrixgiven . Column I(a) Internal energy increases (p) In adiabatic compression

(b) magnitude of the work done is proportionalto change in absolute temperature (q) In the isothermal expansion

(c) magnitude of the work doneis proportional to change in volume (r) In isobaric expansion

(d) Heat transfer is zero (s) Expansion in vacuum

21-.In the adjacent fig-1 and fig-2, two spring mass systems are shown. In both cases one end of thespring is fixed and on the other end blocks are connected. In both cases ground is smooth. At the time t=0 when both springs are in relaxed state, the blocks are given same horizontal velocityV0 as shown. In the following column I, some parameters related to the motionin these cases are mentioned and some values or statement regarding these

parameters are given in the column II. Match the items in the column I with thecorrect descriptions given in the column II and indicate your answer by darkeningappropriate bubbles in the 4 x 4 matrix given

Column I Column II(a) Time period of motion (p) same in both figs

(b) Amplitude of the motion (q) proportional to V0 in both fig(c) Maximum potential energy (r) greater in fig-2 than that of in fig-1

(d) Magnitude of maximum acceleration (s) independent ofV0 in both figs

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22-Two cubical containers R and S of side length x and 2x are containing 2 gm of H2 and 16 gm of Herespectively at same pressure P but at temperatures T1 and T2. respectively. Some properties orparameters about these gas samples are mentioned in the column I and some values or statements aregiven in the column II. Match the items in the column I with the correct descriptions given in thecolumn II and indicate your answer by darkening appropriate bubbles in the 4 x4 matrix given .

Column I Column II(A) Translational kinetic energy per mole (p) smaller than P x3

for the gas in R(B) Translational kinetic energy per unit (q) larger than P x3

volume for the gas in S(C) Total internal energy per mole in S (r) lesser than 3 R T2 /2(D) Total Rotational energy in R (s) mote than 3 R T1 /2

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