# Physics MCQS M CAT



## Amna Amir (Apr 1, 2013)

I request all of you guys please post the physics MCQS for M CAT in this thread 
thanks

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give answers with justification 
1. Weak nuclear force is exhibited during 
a) alpha emission 
b) beta emission 
c) gamma emission 
d) fission

2. the half lives of radioactive elements X and Y 3 minutes and 27 minutes respectively.if the activities of both are same ,then the ratio of number of atoms of X and Y will be
a) 1:9
b) 1:10
C) 1:1
d) 9:1

3.A geigor counter counts radioactive particles by 
a) emitting detectable light pulses when stuck
b) undergoing a chemical reaction with each incident particle

4. starting with sample of pure Cu66 , 7/8 of it decays into Zn in 15 minutes the corresponding half life is 
a)10 min 
b) 15 min 
c) 5 min 
d) 7.5 min


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## CHOCLATE (Jul 5, 2013)

Amna Amir said:


> I request all of you guys please post the physics MCQS for M CAT in this thread
> thanks
> 
> - - - Updated - - -
> ...


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## Amna Amir (Apr 1, 2013)

CHOCLATE said:


> Amna Amir said:
> 
> 
> > I request all of you guys please post the physics MCQS for M CAT in this thread
> ...


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## CHOCLATE (Jul 5, 2013)

1. Weak nuclear force is repulsive having short range in metres also beta ionization is through repulsion so we can predict ionization of beta result in weak nuclear force 
2.half life is inversely proportional to decay constant and decay constant has direct relation with number of atoms so half life and number of atoms are in inverse relation 
half life of x = number of atom of y 
------------- -------------------------- 
half life of y number of atom of x 
3/27 =1/9 
so ratio of x to y is 9:1 
3. My college mam had told me 


Each time a particle enters the counter and ionization current pulse is created which gives a click in the loud speaker or a count in a counter.


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## adnan ahmed (Jul 18, 2013)

Rate of evaporation is equal to rate of condesation that point is called???have u answer so plz tell me


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## CHOCLATE (Jul 5, 2013)

WHEN NUMBER OF MOLECULES EVAPORATING BECOME EQUAL TO NUMBER OF MOLECULES CONDENSING ........ equilibrium is ESTABLISHED BETWEEN LIQUID AND ITS VAPOUR ........... this is called dynamic equilibrium........

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## adnan ahmed (Jul 18, 2013)

correct and good


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## Amna Amir (Apr 1, 2013)

when radioactive nucleus emits a B-particle, the proton -neutron ratio 
a) increases 
b) decreases
c) remain same
d) none

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A curie represents a very strong source of 
a) a-particle
b) b-particle
c) y-particle
d) none


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## ali3 (May 26, 2012)

first one increases second one none


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## Amna Amir (Apr 1, 2013)

ali3 said:


> first one increases second one none


plz @ Ali3 justify your answers

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I know answers too but don't know the reasons that's actually important ...for M CAT 
so I request all of you . plz try to justify your answers at least in Physics..
it helps a lot in clearing concepts


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## CHOCLATE (Jul 5, 2013)

During bets decay mass number does not undergo any change while charge number increases by one .... As number of proton represent charge number so proton number in nucleus increases leading to increase in ratio .......


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## Amna Amir (Apr 1, 2013)

-What other functions do the electron accelerating cylinders have ( in a cathode ray oscilloscope)? 
a) acceleration of the beams 
b) brightness control
c) focus control
d) control of the position of the beam on the screen

( give reason too)


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## Mariamumtaz (Jun 26, 2013)

hi friends...i am posting here some physics questions..please help me solving them..and give reason too..it'll be a great help for me.
Q1
light of frequency 6 into 10*14 hz pases through a diffraction grating with 4 into 10*3 lines/cm.wavelngth of ligth used is 
2 into 10*-9m
5 into 10*-7m
5 into 10*-9m
6 into 10*14m



Q2 A plane polarized light of intensity I is falls normally on thin piece of polaroid.if transmitted light has intensity I/4 then angle of polarization axis of polaroid will be
22.5 degree
60 deg
30 deg
95 deg


Q3 two waves have amplitude in ratio 5:1 produces intrfernc the ratio of maximum to minimum intensity is 
25:1
6:4
9:4
3:2



Q4 time period of simple pendulum inside stationary lift is T.If lift starts moving upward with acceleration g/3 then period will be
T/3
3T
sq.root 3sq.rootT/sq.root2
sq.root 3 T/3(no sq.root on T)




Q5 in what time aftr its motion will begin acc. to equation x=7sin0.5pi t(time) when move from mean to maximum displacemnt.
1second
1/2s
1/4s
1/6s




Q6 what is 273k on celcius scale of temperature
-o.o15
-0.15
0
273


Q7 An ideal carnot engine has efficincy 40%receivs at 500k.if efficiency is 50% the intake temp for same exhaust temp is
600k
900k
700k
800k



Q8 oxygen molecule in earth atmosphere have root mean sq speed 500 m pr s.if relative molecular mass of 02 and helium is 32 ans 4 then approximate rms speed of helium in atmosphere will be
180
1400
1000
2000

THESE QUESTIONS ARE FROM WAVES LIGHT AND IDEAL GAS THERMODYNAMICS..


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