Physics 2015-2016 HSC Science (General) 12th Standard Board Exam Question Paper Solution

The difference in tensions in the string at lowest and highest points in the path of the particle of mass 'm' performing vertical circular motion is:....

a) 2 mg

b) 4 mg

c) 6 mg

d) 8 mg

The body is rotating with uniform angular velocity (w) having rotational kinetic energy (E). Its angular momentum (L) is: ...............

a) `(2E)/ω`

b) `E^2/ω`

c) `E/ω^2`

d) `E/(2ω)`

The S.I. unit of compressibility is __________.

`m^2/"N"`

`"Nm"^2`  

`"N"/"m"^2`

`"(kg)"/"m"^3`

The working of RADAR is based on ...............

a) resonance

b) speed of a star

c) Doppler effect

d) speed of rotation of sun

If two capillary tubes of different diameters are partially dipped in the same liquid vertically, then the rise of liquid ..........

a) is same in both the tubes

b) is more in the tube of larger ~iameter

c) will not be in smaller diameter tube

d) is more in the tube of smaller diameter

A sonometer wire vibrates with three nodes and two antinodes, the corresponding mode of vibration is ...................

a) First overtone

b) Second overtone

c) Third overtane

d) Fourth overtone

Two gases exert pressure in the ratio 3: 2 and their densities are in the ratio 2: 3, then the ratio of their R.M.S. velocities is ...........

2:3

3:2

2:1

1:2

Draw a diagram showing all components of forces acting on a vehicle moving on a curved banked road. 

Derive an expression for critical velocity of a satellite revolving around the earth in a circular orbit.

Draw a neat labelled diagram of rise of liquid in capillary tube showing different components of tension (force).

State any four assumptions of kinetic theory of gases.

A tube open at both ends has length 47 em. Calculate the fundamental frequency of air column. (Neglect end correction. Speed of sound in air is 3.3 x 10²m/s}

A uniform solid sphere has a radius 0.1 m and density 6 x 103 kg/m3• Find its moment of inertia about a tangent to its surface.

A particle executes S.H.M. with a period of 10 seconds. Find the time in which its potential energy will be half of its total energy.

A stone of mass 2 kg is whirled in a horizontal circle attached at the end of 1.5m long string. If the string makes an angle of 30° with vertical, compute its period. (g = 9.8 m/s²)

State Kepler's laws of planetary motion.

Obtain an expression for torque acting on a body rotating with uniform angular acceleration.

A steel wire having cross-sectional area 2 mm2 is stretched by ION. Find the lateral strain produced in the wire. (Given : Y for steel = 2 x 10¹¹ N / m2, Poisson's ratio δ = 0.29)

A body cools from 62°C to 54°C in 10 minutes and to 48°C in the next 10 minutes. Find the temperature of the surroundings.

Explain the formation of stationary waves by analytical method. Show that nodes and antinodes are equally spaced in stationary waves.

The speed limit for a vehicle on road is 120 km/ hr. A policeman detects a drop of 10% in the pitch of horn of a car as it passes him. Is the policeman justified in punishing the car driver for crossing the speed limit? (Given: Velocity of sound= 340 m/s)

Define practical simple pendulum

Show that motion of bob of the pendulum with small amplitude is linear S.H.M. Hence obtain an expression for its period. What are the factors on which its period depends?

The total free surface energy of a liquid drop is `pisqrt2` times the surface tension of the liquid. Calculate the diameter of the drop in S.l. unit.

A parallel beam of light travelling in water is incident obliquely on a glass surface. After refraction its width ..............

a) decreases

b) increases

c) remains the same

d) becomes zero

If 'a' is the aperture of telescope and A. is the wavelength of light then resolving power of telescope is .............

a) `lambda/(1.22a)`

b) `(1.22a)/lambda`

c) `(1.22 lambda)/a`

d) `a/(1.22lambda)`

From earth's surface, ionospheric layer of atmosphere lies between ............

(a) 12 km to 50 km

(b) 50 km to 80 km

(c) 80 km to 400 km

(d) 400 km to 700 km

The kinetic energy of emitted photoelectorns is independent of ............

(a) frequency of incident radiation.

(b) intensity of incident radiation.

(c) wavelength of incident radiation

(d) collector plate potential

In hydrogen atom Balmer series is obtained when the electron jumps from ............ .

(a) higher orbit to first orbit

(b) first orbit to a higher orbit

(c) higher orbit to the second orbit

(d) second orbit to a higher orbit

The fraction of the total current passing through the galvanometer is ............ .

a) `S/(S+G)`

b) `G/(S+G)`

c) `(S+G)/G`

d) `(S+G)/S`

A meter gauge train is heading north with speed 54 km/hr in earth's magnetic field 3 x 10^-4T. The e.m.f. induced across the axle joining the wheels is ..........

(a) 0.45 mV

(b) 4.5 mV

(c) 45 mV

(d) 450 m V

Distinguish between intrinsic and extrinsic semiconductor. (Give any two points).

Draw the block diagram of a receiver in communication system

A point is situated at 6.5 em and 6.65 em from two coherent sources. Find the nature of illumination at the point, if wavelength of light is 5000 Å

Draw the diagrams showing the dipole moments in paramagnetic substance when external magnetic field is (a) absent (b) strong

A voltmeter has a resistance of 100 Ω. What will be its reading when it is connected across a cell of e.m.f. 2V and internal resistance 20Ω?

The susceptibility of magnesium at 300K is 1.2 x 10^-5. At what temperature will the susceptibility increase to 1.8 X 10^-5?

What is de Broglie wavelength of an electron accelerated through 25000 volt?

Draw the schematic symbols for AND, OR, NOT and NAND gate

Using analytical method for interference bands, obtain an expression for path difference between two light waves.

State the law of radioactive decay.

Derive the mathematical expression for law of radioactive decay for a sample of a radioactive nucleus

Represent Radioactive Decay curve using relation `N = N_o e^(-lambdat)` graphically

Determine the change in wavelenght of light during its passage from air to glass, if the refracrtive index of glass with respect to air is 1.5 and the frequency of light is 5 x 10¹⁴ Hz. Find the wave number of light in glass (velocity of light in air c = 3 X 10⁸ m/s)

Light of wavelength 3000Å falls on a metal surface having work function 2.3 eV. Calculate the maximum velocity of ejected electrons

(Planck's constant h = 6.63 x 10^-34 J.s., Velocity of light c = 3 x 10⁸ m/s, mass of an electron = 9.1 x 10^-31 kg)

What is electromagnetic induction?

Prove theoretically  (electromagnetic induction) `e = (dphi)/(dt)`

A potentiometer wire has length of 2m and resistance 10^Ω. It is connected in series with resistance 990Ω and a cell of e.m.f. 2V. Calculate the potential gradient along the wire.

With the help of a neat diagram, describe the construction and working of van de Graff generator.

A moving coil galvanometer has a resistance of 25Ω and gives a full scale deflection for a current of 10mA. How will you convert it into a voltmeter having range 0 - 100 V?