# JEE Main Physics question – JEE Main Physics MCQ

By | April 4, 2017

In JEE main exam there were 90 questions comes from Mathematics, physics and Chemistry. Here on this page, we have provided the JEE Main 2017 question here is 10 Physics question of Physics. On other posts, we have also mentioned the JEE Main Examination Physics Question Answer as well other JEE Main Exam Answer keys.

JEE Main Physics Question 2017 | Joint Entrance Exam 2017 Main  Answer keys

(Q- 31 )A radioactive nucleus A with a half-life T decays into a nucleus B. At t = 0, there is no nucleus B. At some time T, the ratio of the number of B to that of A is 0.3. Then, given by:

• t= T/log (1.3)
• t= T/2 log 2/log 1.3
• t= T Log1.3/log 2
• t= T log (1.3)

(Q-32 ) The following observations were taken for determining surface tension T of water by the capillary method: Diameter of the capillary, D = 1.25 X 10-2 m rise of water, h=1.45×10-2 m. Using g =9.80m/s2 and the simplified relation T= rhg/2 X 10 3N/m, the possible error in surface tension is closest to

1. 10%
2. 15%
3. 5%
4. 4%

(Q-33) An electron beam is accelerated by a potential difference V to hit a metallic target to produce X-rays. It produces continuous as well as characteristic X-rays. If min is the smallest possible wavelength of X-ray in the spectrum, the variation of log min with log V is correctly represented in:

(Q-34) The moment of inertia of a uniform cylinder of length I and radius R about its perpendicular bisector is I. What is the ratio I/R such that the moment of inertia is minimum?

JEE Main Exam Quesiton 2017 Physics

(Q-35) A slender uniform rod of mass M and length I am pivoted at one end so that it can rotate in a vertical plane (see figure). There is negligible friction at the pivot. The free end is held vertically above the pivot and then released. The angular acceleration of rod when it makes an angle 0 with the vertical is:

1. 2g/3l cos Q
2. 3g/2/ sing Q
3. 2g/3l/ sin Q
4. 3g/2l cos Q

Q-36. C and c are specific heats at constant pressure and constant volume respectively it is observed that. Cp-c0 = a for hydrogen gas Co-c0=b for nitrogen gas. The correct relation between a and b is:

Q-37. A copper ball of mass 100 gm is at a temperature T. It is dropped in a copper calorimeter of mass 100gm, filled with 170 gm of water at room temperature. Subsequently, the temperature of the system is found to be 75.c. T is given by : (given : room temperature =30.C, specific heat of copper = 0.1 cal/gm’s )

1. c
2. c
3. c
4. c

Q- In amplitude modulation, sinusoidal carrier frequency used denoted by WC and the signal frequency is denoted by Wm. The bandwidth (nm) of the signal is such that wn<<wc. Which of the following frequencies is not contained in the modulated wave?

# JEE Exam Physics Questions

Q-39. The temperature of an open room of volume 30m3 increases from 17.c ti 27.c due to the sunshine. The atmospheric pressure in the room remains 1X10.5 pa. if n1 and nf are the numbers of molecules in the room before and after heating, then nf –n1 will be;

Q-40. In a young’s double slit experiment, slits are separated by 0.5 mm, and the screen is placed 150 cm away. A beam of light consisting of two wavelengths, 650 nm and 520 nm, Ais used to obtain interference fringes on the screen. The least distance from the common central maximum to the point where the bright fringes due to both the wavelengths coincide is:

Q- 41. A particleAnof mass m and initial velocity v collide with a particle B of mass m/2 which is at rest. The collision is head on, and elastic. The ratio of the de-Broglie wavelengths A to B after the collision is:

### Joint entrance exam 2017 physics question

Q- 42. A magnetic needle of magnetic moment 6.7×10-2 Am 2 and moment of inertia 7.5 x10-6 kg m2 is performing simple harmonic oscillations in the magnetic field of 0.21 T. Time taken for the 10 complete oscillations is:

• 8076 s
• 65s
• 8089s
• 98 s

Q-43.  An electric dipole has a fixed dipole moment p-, which makes angle o with respect to the x-axis. When subjected to an electric field E1 = E1 it experiences a torque ti = tk. when subjected to another electric field e2 = it experiences a torque t2= t1. The angle o is 1- 90. 2-30. 3- 45’ 4- 60’

Q- 44.  An observation is moving with half the speed of light towards a stationary microwave source emitting waves at frequency 10 GHz. What is the frequency of the microwave measured by the observer? (Speed of light = 3×10 8 MS-1)

1.     12.1 GHz
2. 17.3 GHz
3. 15.3 GHz
4. 10.1 GHz

Q- . The following observation was taken for determining surfaces tension T of water by capillary method. Diameter of capillary, D =1.25 x 10-2m rise of water, h=1.45×10-2m. Using g =9.80 m/s2 and the simplified relation T= rhg/2 X 10 3 N/M, the possible error in surface tension is closest to

1. 1.5%
2. 2.4%
3. 10%
4. 0.15%

Q- . Some energy levels of a molecule are shown in the figure. The ratio of the wavelenght r is given below.

1. r=2/3
2. r=3/4
3. r= 1/3
4. r= 4/3

Q-  A body of mass m = 10-2 kg is moving in a medium and experience and experience frictional forces F= -kv2, Its initial speed is v=10 ms -1, If after 10 s, its energy is 1/8 mv 02, the value of K will be

1. 10-3 kg s-1
2. 10-4 kg m-1
3. 10-1 kg m-1 s-1
4. 10 -3 kg m -1

Q- Which of the following statements is false?

1- IN a balanced wheater stone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.

2- A rheostat can be used as a potential divider.

3- Kirchoff’s second law represents energy conservation.

4- Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.

Q-  A capacitance of 2 u F is required in an electrical circuit across a potential difference of 1.0 k.V. A large number of 1 u.F Capacitors are available which can withstand a potential difference of not more than 33 V.

Q- In the given circuit diagram when the cirrent reaches stady state in the circuit, the charge on the capacitor of capacitance C will be:

Q- In the above circuit the current in each resistances is:

1. 0.25 A
2. 0.5 A
3. 0A
4. 1A

Q- In amplitude modulation, sinusoidal carrier frequency used is denoted by WC and signal frequency denoted by Wm. The bandwidth ( Wm) of the signal is such that Wm << which of the following frequencies is not contained in the modulated wave?

Q-  In a common emitter amplifier circuit using an n-p-n transistor, the phase differences between the input and the output voltages will be:

1. 90′
2. 135′
3. 180′
4. 45′

Q- A copper ball of mass 100 gm is at a temperature T. it is dropped in a copper calorimeter of mass 100 gm, filled with 170 gm of water at room temperature. Subsequently, the temperature of the system found to be 75’C. T is given by: ( Given : room temperature = 30.C, specific heat of copper = 0.1 cal/gm ‘c

1. 885.c
2. 1250.c
3. 825.c
4. 800.c

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