J physics 21

A man stands 4m in front of a plane mirror. If the mirror is moved 1m towards the man, the distance between him and his new image is?

If a sound wave goes from a cold air region to a hot air region, its wavelength will?

Which of the units of the following physical quantities are derived?

I. Area
II. Thrust
III. Pressure
IV. Mass

Two bodies have masses in the ratio3:1. They experience forces which impart to them, acceleration in the ratio 2:9 respectively. Find the ratio of forces the masses experienced

A source of sound produces waves in air of wavelength 1.65m. If the speed of sound in air is 330ms⁻¹, the period of vibration in air is?

An astronomical telescope is said to be in normal adjustment when the?

If the frequency of an emitted x-ray is 1.6 x 10¹⁶Hz, the accelerating potential is? [e = 1.6 x 10¹⁹J, h = 6.63 x 10^-34Js]

The lowest note emitted by a stretched string has a frequency of 40Hz. How many overtones are there between 40Hz and 180Hz?

The inner diameter of a test tube can be measured accurately using a?

A man will exert the greatest pressure when he?

A 2H inductor has negligible resistance and is connected to a 50/π Hz A.C supply. The reactance of the inductor is?

When the breaks in a car are applied, the frictional force on the tyres is?

A solid weighs 10.00N in air, 6N when forcefully immersed in water, and 7.0N when fully immersed in a liquid, X. Calculate the relative density of the liquid X.

A given mass of gas has a pressure of 80 Nm⁻² at a temperature of 47° C. If the temperature is reduced to 27° C with volume remaining constant, the new pressure is?

Particles of mass 10⁻²kg is fixed to the tip of a fan blade which rotates with angular velocity of 100rad⁻¹. If the radius of the blade is 0.2m, the centripetal force is?

If the fraction of the atoms of a radioactive material left after 120 years is 1/64, what is the half-life of the material?

0.5kg of water at 10ºC is completely converted to ice at 0ºC by extracting (88000) of heat from it. If the specific heat capacity of water is 4200jkg¹ºC. Calculate the specific latent heat of fusion of ice.

Which of the following instruments may be used to measure relative humidity?

Calculate the mass of ice that would melt when 2kg of copper is quickly transferred from boiling water to a block of ice without heat loss (specific heat capacity of copper = 400Jkg¹k^-1, latent heat of fusion of ice = 3.3 x 10 ⁵Jkg^-1)

I. A liquid boils when its saturated vapor pressure is equal to the external pressure
II. Dissolved substances in pure water lead to an increase in the boiling point.
III. When the external pressure is increased, the boiling point increases.
IV. Dissolved substances in pure water decreases the boiling point 

Which of the above combinations are peculiarities of the boiling point of a liquid?

A ball of mass 0.1kg is thrown vertically upwards with a speed of 10ms⁻¹ from the top of a tower 10m high. Neglecting air resistance, its total energy just before hitting the ground is? (Take g = 10ms⁻²)

A boy standing some distance from the foot of a tall cliff claps his hands and hears an echo 0.5s later. If the speed of sound is 340ms⁻¹, how far is he from the cliff?

The temperature gradient across a copper rod of thickness 0.02m, maintained at two temperature junctions of 20ºC and 80ºC respectively is?

A piece of substance of specific heat capacity 450Jkg^-1k^-1 falls through a vertical distance of 20m from rest. Calculate the rise in temperature of the substance on hitting the ground when all its energies are converted into heat. [g = 10ms²]

When the temperature of a liquid increases, its surface tension

A ball of mass 0.5kg moving at 10ms^-1 collides with another ball of equal mass at rest. If the two balls move off together after the impact, calculate their common velocity.

The equation of a wave traveling along the positive x-direction is given by; y = 0.25 x 103 sin (500t - 0.025x). Determine the angular velocity of the wave motion. 

A gas at a volume of V0 in a container at pressure p0 is compressed to one-fifth of its volume. What will be its pressure if the magnitude of its original temperature T is constant?

The motion of a body is simple harmonic if the?

The slope of the straight line displacement-time graph indicates?

The velocities of light in air and glass are 3.0 x 10⁸ms^-1 and 2.0 x 10⁸ms^-1 respectively. If the angle of refraction is 30º, the sine of the angle of incidence is? 

A lead bullet of mass 0.05kg is fired with a velocity of 200ms^-1 into a block of mass 0.95kg. Given that the lead block can move freely, the final kinetic energy after impact is?

In a series R-L-C circuit at resonance, the voltages across the resistor and the inductors are 30V and 40V respectively. What is the voltage across the capacitor?

A car of mass 800kg attains a speed of 25m/s in 20secs. The power developed in the engine is?

The inside portion of part of a hollow metal sphere of diameter 20cm is polished. The portion will therefore form a?

Which of the following is not a vector quantity?

A certain radioactive source emits radiation that was found to be deflected by both magnetic and electric fields. The radiation is?

If the stress on a wire is 10⁷NM^-2 and the wire is stretched from its original length of 10.00m to 10.05m. The young's modulus of the wire is?

Calculate the heat energy required to vaporize 50g of water initially at 80ºC if the specific heat capacity of water is 4.23jg^-1k (specific latent heat of vaporization of water is 2260jg^-1)

Which of the following is not correct about the molecules of a substance in a gaseous state. They?