Physics Important Problems and Solution Free || If Ro is the radius of the first (n = 1) orbit in a hydrogen atom, the radius of the fourth (n = 4) orbit is given by || Potential energy per unit volume u of a strained wire is

Learn To Converge Your Dreams with Durgam Vigyan Sansthana.

Dear Friends, You can watch a video solution to these problems on my youtube channel link is here-

I am working for you so it is your responsibility that you should help me by subscribing to me on my youtube channel...After that, I will work with extra energy and happiness.

Tap here to Subscribe it will be helpful...

Q.1 If Ro is the radius of the first (n = 1) orbit in a hydrogen atom, the radius of the fourth (n = 4) orbit is given by

a) 16Ro

b) 4Ro

c) Ro/4

d) Ro/16

For The Solution Tap Here

Q.2 Potential energy per unit volume u of a strained wire is:

a) Stress x Strain

b) Stress x Strain/4

c) Stress x Strain/2

d) 3 x Stress x Strain/4

For The Solution Tap Here

Q.3 Two lenses have dispersive power in a ratio of 2:3 these glasses are used to make an achromatic lens of focal length of 20 cm the value of focal lengths of two lenses are:

a) F1 = 5 cm, F2 = -10 cm

b) F1 = -10 cm, F2 = 10 cm

c) F1 = 6.67 cm, F2 = -10 cm

d) F1 = 10 cm, F2 = -10 cm

For The Solution Tap Here

Q.4 A capacitor with air between its plates has a capacitance of 8 micro Farad. Its capacitance on introducing a dielectric with a dielectric constant of 6 between its plate is:

a) 48 uF

b) 40 uF

c) 16 uF

d) 32 uF

For The Solution Tap Here

Q.5 For a vendor was gas the inversion temperature at low pressure is:

a) 27a/bR

b) 2a/Rb

c) ab/8R

d) a/8Rb

For The Solution Tap Here

Q.6 The wavelength of K alpha x-ray line of an element of atomic number Z = 11 is λ. the wavelength of K alpha line of another element of atomic number Z is λ then Z is:

a) 11

b) 44

c) 6

d) 4

For The Solution Tap Here

Q.7 The ratio of most probable speed and the average speed of a gas enclosed in a vessel is:

a) √兀/4

b) 1

c) 2/√兀

d) √兀/2

For The Solution Tap Here

Q.8 A rectangular glass plate of refractive index 1.5 is used as a polarizer the corresponding polarising angle will be:

a) 43.7 degree

b) 33.7 degree

c) 56.3 degree

d) 23.4 degree

For The Solution Tap Here

Q.9 When the plate voltage applied to a diode valve is changed from 48 volts to 50 volts, the plate current increases from 60 mA to 70 mA what is the dynamic plate resistance of the diode?

a) 200 ohm

b) 180 ohm

c) 150 ohm

d) 120 ohm

For The Solution Tap Here

Q.10 Viscosity of a gas is due to the transport of

a) Momentum

b) Energy

c) Mass

d) None of these

For The Solution Tap Here

Q.11 When the current in a coil changes from 8 A to 2 A in 3 x 10-3 s. The EMF induced in the coil is 2 V the self-inductance of the coil is:

a) 1mH

b) 5 mH

c) 20 mH

d) 10 mH

For The Solution Tap Here

Q.12 According to Planck's the average energy of an oscillator with frequency v (nu) and its internal energy multiples of

a) kT

c) 3kT/2

d) 0

For The Solution Tap Here

Q.13 A dipole is formed by two charges of 5 uC and- 5 uC at a distance of 8 mm. Find the electric field

i) at a point 25 cm away from the dipole center at its axis and

ii) at a point 20 cm away on a line perpendicular to the axis and passing through its center.

a) 6 x 106N/C, 4.5 x 104N/C

b) 4.6 x 104N/C, 4.5 x 104N/C

c) -4.6 x 104N/C, 4.5 x 104N/C

d) 4.6 x 104N/C, 6 x 106N/C

For The Solution Tap Here

Q.14 Compute the magnetic induction in the air at a point 10 cm from a long straight wire carrying a current of 20 A:

a) 3 x 10-5 T

b) 4 x 10-5 T

c) 5 x 10-5 T

d) 6 x 10-5 T

For The Solution Tap Here

Q.15 The shape of the Lissajous figures depends on:

a) the amplitude of the superposing Waves

b) frequencies of superposing waves

c) the phase difference between the supervising waves

d) all of the above

For The Solution Tap Here

Q. 16 For µ0 = 1.544 and µe = 1.544 and λ = 6500 Å, the thickness of a quarter wave plate is

a) 10.0 µm

b) 11.6 µm

c) 0.25 µm

d) 0.28 µm

For The Solution Tap Here

Q.17 The displacement current arises due to:

a) positive charges only

b) negative charges only

c) both positive and negative charges

d) time-varying electric field

For The Solution Tap Here

Q.18 A block of Steel heated to 100 degrees Celsius is left in a room to cool which of the following curve shown in figure represents correct behaviour:

a) A

b) B

c) C

d) None

For The Solution Tap Here

Q.19 The streamline flow of an incompressible and non-viscous liquid is described by:

a) Boyle's law

b) Poiseuille's law

c) Archimedes principle

d) Bernoulli's principle

For The Solution Tap Here

Q.20 In a young's double slit experiment the slit separation is 0.12 mm the wavelength of light used is 5893 Å and the interference pattern is observed on a screen 1 m away the separation between successive bright fringes will be:

a) 6.50 mm

b) 5.50 mm

c) 4.91 mm

d) 4.50 mm

For The Solution Tap Here