J physics 20

The mass of a proton is approximately equal to that of

A solid weighs 4.8g in air, 2.8g in water and 3.2g in Kerosine. The ratio of desity of the solid to that of the kerosine is

What is the cost of running five 50W lamps and four 100W lamps for 10 hours if electrical energy costs 2 Kobo per KWh?

A transformer has 300 turns of wire in the primary coil and 30 turns in the secondary coil. If the input voltage is 100 volts, the input voltage is

The fiqure above represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is 40 o, then the value of W is

A hydrometer is an instrument for measuring the 

Which of the following statements about defects of vision is/are CORRECT? 

I. For a long sighted person, close objects appear blurred

II. For a short sighted person, distant objects appear blurred 

III. Short sight is corrected by using a pair of converging lenses

Which of the following statements about radioactivity is true?

(i) Alpha particle is positively charged

(ii) Beta particle is negatively charged

(iii) Gamma ray is neutral

(iv) Beta particle has the  same mass as helium atom

(v) Gamma ray is charged.

The effect of closing the key K in the circuit shown in the figure above would be to?

A convex mirror is used as a driving mirror because 

I. its image is erect     

II. It has a large field of view

III. It has a long focal length 

Identify the CORRECT statement(s)

Under which of the following conditions is work done?

A few grains of table salt were put in a cup of cold water, kept at constant temperature and left undistributed. Eventually all the water tested salty. This action is due to?

When a sound wave passes from air into water its 

A machine gun with a mass of 5kg fires a 50g bullet at a speed of 100 ms^-1. The recoil speed of the machine gun is

Which of the following instruments consumes the highest current?

I. Electric iron    250V    1kW
II. Television set    220V    110W
III. Torchlight    6V    30W
IV. Immersion heater    110V    500W

If a source of solid is moving, a stationary listener will hear a sound of different frequency. This is called?

Heat is supplied uniformly at the rate of 100W to 1.0 x 10^-2 kg of a liquid for 20 seconds. If the temperature of the liquid rises by 5°C, then the specific heat capacity of the liquid is

One of the following readings represents the measurement of the measurement of the length of a metal rod using vernier callipers. Taking the reading accuracy into consideration, the most likely one is

The linear expansivity of brass is 2 x 10^-5°C^-1. If the volume of piece of brass is 2 x 10cm³ at 0 °C. What will be its volume at 100 °C?

Which of the following conditions are necessary and sufficient for total internal reflection to take place at the boundary between two optical media?

I. Light is passing from optical denser medium to optically less dense medium

II. Light is passing from optically less dense medium to optically denser medium to optically denser medium

III. Angle of incidence is greater 

IV. Angle of incidence is lesser

A substance has half of 3 min. After 6 min, the count rate was observed to be 400. What was its count rate at zero time?

The lower and upper fixed points marked on a Mercury-in-glass thermometer are 210mm. The end of the mercury column in the tube is 49mm above the lower fixed point in a room. What is the temperature of the room in degrees Celsius?

Which of the following statements on the use of X-rays is incorrect? X-rays are used

Which of the following pairs is NOT part of the electromagnetic spectrum? 

I. Radio waves

II. Beta rays

III. Gamma rays

IV. Alpha rays

Two mirrors of the same length are arranges as show in the diagram. A ray of light NO strikes the system at O and emerges along PQ. The emergent ray has been deviated through

A ship travelling towards a cliff receives the echo of its whistle receives the echo of its whistle after 3.5 seconds. If the speed of sound in air under the prevailing conditions is 250ms⁻¹, how much closer is the ship to the cliff?

Consider the three forces acting at O and in equilibrium as shown in the figure. Which of the following equations is/are CORRECT?

I. P₁ cos θ₁ = P₁ cos θ₂

II. P₃ = P₁ cos θ₄ + P₂ cos θ₂

III. P₁ sin θ₁ = P₂ sin θ₂

The refractive index of a liquid is 1.5. If the velocity of light in a vacuum is 3.0 x 10 8ms?1, the velocity of light in the liquid is 

In an experiment in which molten naphtha-line is allowed to cool, the cooling curve i n the figure was obtained. The temperature 80 o0c is known as the

Natural radioactivity consists of emission___

The force required to make an object of mass m, travelling with velocity v, turn in a circle of radius r is

A magnetic needle is suspended first at the earth's north magnetic pole and then at a point on the magnetic equator. The respective angles between the needle and the horizontal are 

If in a simple pendulum experiment the length of the inextensible string is increased by a factor or four, its period is increased by a factor of?

In what range of temperature is the expansion of water anomalous?

Which of the following can be described as high tension transmission? 

Two divers G and H are at depths 20m and 40m respectively below the water surface in a lake.
The pressure on G is P₁ while the pressure on H is P₂.
If the atmospheric pressure is equivalent to 10m of water, then the value of
^P₂/_P1 is?

In the study of Physics, temperature and heat are often confused with each other. Which of the following statements correctly defines these two elements?

In the figure, the value of R is