Other Physics · JEE Main previous year questions

2012 11 questions

1. Q402012 · 26 May 2012 · Shift 1
   
   1. A.Depends on $H$
   2. B.$1:1$
   3. C.$2:2$
   4. D.$1:2$
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   Answer: B

2. Q432012 · 26 May 2012 · Shift 1

   The disturbance $y(x,t)$ of a wave propagating in the positive $x$-direction is given by $y=\frac{1}{1+x^2}$ at time $t=0$ and by $y=\frac{1}{[1+(x-1{)}^2]}$ at $t=2\mathrm{s}$, where $x$ and $y$ are in meters. The shape of the wave disturbance does not change during the propagation. The velocity of wave in $m/s$ is

   1. A.$2.0$
   2. B.$4.0$
   3. C.$0.5$
   4. D.$1.0$
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   Answer: C

3. Q552012 · 26 May 2012 · Shift 1

   Photoelectrons are ejected from a metal when light of frequency $\nu$ falls on it. Pick out the wrong statement from the following.

   1. A.No electrons are emitted if $\nu$ is less than $W/h$, where $W$ is the work function of the metal
   2. B.The ejection of the photoelectrons is instantaneous.
   3. C.The maximum energy of the photoelectrons is $h\nu$.
   4. D.The maximum energy of the photoelectrons is independent of the intensity of the light.
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   Answer: C

4. Q392012 · 12 May 2012 · Shift 1

   Assuming the earth to be a sphere of uniform density, the acceleration due to gravity inside the earth at a distance of $r$ from the centre is proportional to

   1. A.$r$
   2. B.$r^{-1}$
   3. C.$r^2$
   4. D.$r^{-2}$
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   Answer: A

5. Q602012 · 12 May 2012 · Shift 1

   Which of the following Statements is correct?

   1. A.The rate of radioactive decay cannot be controlled but that of nuclear fission can be controlled.
   2. B.Nuclear forces are short range, attractive and charge dependent.
   3. C.Nuclei of atoms having same number of neutrons are known as isobars.
   4. D.Wavelength of matter waves is given by de Broglie formula but that of photons is not given by the same formula
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   Answer: A

6. Q332012 · 7 May 2012 · Shift 1

   A car of mass $1000\mathrm{kg}$ is moving at a speed of $30m/s$. Brakes are applied to bring the car to rest. If the net retarding force is $5000\mathrm{N}$, the car comes to stop after travelling $d\mathrm{m}$ in $t\mathrm{s}$. Then

   1. A.$d=150$, $t=5$
   2. B.$d=120$, $t=8$
   3. C.$d=180$, $t=6$
   4. D.$d=90$, $t=6$
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   Answer: D

7. Q342012 · 7 May 2012 · Shift 1

   An engine pumps water continuously through a hose. Water leaves the hose with velocity $v$ and $m$ is mass per unit length of the water jet. If this jet hits a surface and came to rest instantaneously, the force on the surface is

   1. A.$m{v}^3$
   2. B.$m{v}^2$
   3. C.$\frac{1}{2}m{v}^2$
   4. D.$\frac{1}{2}m{v}^3$
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   Answer: B

8. Q382012 · 7 May 2012 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
   Show answer

   Answer: B

9. Q402012 · 7 May 2012 · Shift 1
   
   1. A.$OA$
   2. B.$OC$
   3. C.$OD$
   4. D.$OB$
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   Answer: A

10. Q412012 · 7 May 2012 · Shift 1
    
    1. A.$\frac{\ell }{\sqrt{2\pi }}$
    2. B.$\frac{\ell }{\sqrt{3\pi }}$
    3. C.$\frac{\ell }{3\pi }$
    4. D.$\frac{\ell }{2\pi }$
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    Answer: A

11. Q422012 · 7 May 2012 · Shift 1

    The heat radiated per unit area in 1 hour by a furnace whose temperature is $3000\mathrm{K}$ is ($\sigma =5.7\times 10^{-8}\mathrm{W}{\mathrm{m}}^{-2}{\mathrm{K}}^{-4}$)

    1. A.$1.7\times 10^{10}\mathrm{J}$
    2. B.$1.1\times 10^{12}\mathrm{J}$
    3. C.$2.8\times 10^8\mathrm{J}$
    4. D.$4.6\times 10^6\mathrm{J}$
    Show answer

    Answer: A