Test Series-15

## Instructions

• Your test contains 20 multiple choice questions with only one answer
• This is 30 min test.Please make sure you complete it in stipulated time
• You can Finish this test any time using 'Submit' button.
• Once finished you get a chance to review all question with correct answers and their solutions.

1.A body is moving in straight line with a initial velocity u0 and constant acceleration a0 . It covers a distance 40 m in the 4th sec and distance of 60 m in the 6th sec. Which of them are true?
• u0 =5m/s ,a0=10 m/s2
• u0 =5m/s ,a0=15 m/s2
• u0 =15m/s ,a0=5 m/s2
• u0 =10m/s ,a0=5 m/s2

2. The effective capacitance of a number of capacitor connected in series is p F ,When one of the capacitor is removed,the The effective capacitance is q F.The capacitance of the capacitor which is removed
• (q-p)
• pq/p+q
• pq/q-p
• None of these

3. An elastic spring of unstretched lenght L and force constant k is stretched by a small length a .It is further stretched by another small lenght b.The workdone in first stretching and second stretching is W1 and W2. Which of the following is true
• W1=Ka2/2 ,W2=Kb2/2
• W1=Ka2/2 ,W2=Kb(2a+b)/2
• W1=Ka2/2 ,W2=K(a2+b2)/2
• W1=Ka2/2 W2= K(a+b)2/2

4..Which all is conserved in Nuclear reactions
• Energy only
• Mass only
• Momentum only
• Mass,energy and momentum

5.Two parallel plate air capacitors have their plate areas 100 cm2 and 500 cm2 respectively.If they have the same charge and potential and the distance between the plates of the first capacitor is 0.5 mm, what is the distance between the plates of the second capacitor?
• .25cm
• .1 cm
• .60cm
• 1cm

6. When 30 J of work was done on a gas,50 J of heat energy was released. The final internal energy of the is 90 J.The initial internal energy of the gas is?
• 110J
• 70J
• 10J
• 170J

7. Two person X and Y,each carrying a source of sound of frequency k are standing a few meters apart in a quiet field. X starts moving towards Y with the velocity a .If b is the speed of sound,how many beats will be heard per sec by A?
• ka(b-a)
• 2ka/(a+b)
• 2ka/b
• ka/b

8. A big drop of water is broken into large number of small drops? The surface energy would
• Remains unchanged
• will increase
• will decrease
• Not enough information

9.A U tude containing a liquid is acclerated horizontally with constant acceleration a .The separation between the limb's is L. The Difference in the height of the liquid in the two arms would be
• L(a/g)1/2
• aL/gL
• L/2
• a2L/g2L

10.Two electron are released towards each other with equal velocities of 106 m/s. What is the closest distance between them?
• 3.56X10-10 m
• 2.56X10-7 m
• 1.6X10-10 m
• 2.56X10-10 m

11. A monochromatic point source of light is at a distance of .2 m from a photo electric cell,the saturation current and cutoff voltage are 18mA and .6 Volt respectively.If the same source is placed at .6m away from the photo electric cell,then
• stopping voltage=.6 V,Saturation current =2mA
• stopping voltage=.6 V,Saturation current =2mA
• stopping voltage=.6 V,Saturation current =3mA
• stopping voltage=.16 V,Saturation current =2mA

12. A pool ball of mass m and radius r is given initial sliding velocity v0( no rotation) on a horizontal pool table.how long will it take for ball to start pure rolling if the coefficent of friction between ball and table is k?
• 2v0/7kg
• 7v0/2kg
• v0/kg
• All of the above
13. A elevator of Mass M moves upward with accleration .3g pulled by the cable. What is the normal force exerted by the elevator floor on the person of mass m standing on the elevator?
• Mg
• .7mg
• mg
• 1.3mg
14. A proton is released from rest in a region of steady and uniform Electric Field E and Magnetic Field B which are parallel to each other. The proton trajactory will be
• Circle
• Straight line
• helix
• cycloid
15. Three capacitors have capacitances of C F, 2C F and 3C F respectively. They are first connected to have maximum capacitance and then connected to have minimum capacitance. Find the ratio of maximum capacitance to minimum capacitance.
• 6
• 5
• 11
• None of these
16. When a ray of light enters a glass slab from air
• Wavelenght decreases
• Frequency increase
• Neither wavelenght nor frequency changes
• None of these
17. A flatbad truck carries a box. The coefficent of friction between the box and truck is .3 What is the maximum acceleration the driver can have so that box does not slide? Take g=10m/s2
• Data not sufficent
• .3 m/s2
• 3m/s2
• None of these
18. A heater boils a certain quantity of liquid in time x. Another heater boils the same quantity of liquid in time y. If the both the heater are connected in parallel,the combination will boil the liquid in time
• (1/x)+(1/y)
• x+y
• (x+y)/2
• (xy)1/2
19. If the distance between the earth and sun were half its present value,the number of days in the years would have been
• 129
• 730
• 181
• 64.5
20. Which of these is false for movement of alpha and beta particles in electric and magnetic field
• Both the article move in circular path in magnetic field
• curvature of path of beta particle is more than the curvature of alpha particle in magnetic field
• Deflection of alpha particle is opposite to that beta particle in electric field
• None of these