physics Questions

Dimensions of frequency is

Consider the following statements made about the magnification m of an image produced by a convex lens. As the object distance u increases:

(A) From u = 0 to u = f, m increases.

(B) From u = f to u = 2f, m decreases.

(C) From u = 2f to u = ∞, m increases.

Of the above statements:

A simple microscope has a convex lens of focal length 5 cm. If the least distance of distinct vision is 25 cm, the magnification of the microscope in normal adjustment is:

A person hears a sound intensity level of 10 dB when a speaker produces a sound output of 5 W. When the sound output of the speaker is increased to 50 W, the sound intensity level that the person hears is:

A sound wave of intensity 2.0 µW/m² passes normally through a surface area of 10 cm². The amount of energy passing through the area in 1 hour is:

The frequencies of the fundamental and the first overtone of a stretched string fixed at both ends are $f_1$ and $f_2$ respectively. What is the ratio $\frac{f_1}{f_2}$?

An observer is moving at a speed of 40 m/s towards a stationary siren sounding at a frequency of 600 Hz. If the speed of sound in air is 320 m/s, what is the frequency of the sound heard by the observer?

Two bodies having thermal capacities in the ratio 1 : 4 are heated to a few degrees above room temperature and allowed to cool. If their rates of fall of temperature are the same at a particular instant, then their rates of loss of heat would be in the ratio:

10 g of steam at 100 °C is mixed with 10 g of ice at 0 °C. The final temperature of the mixture will most likely be:

An ideal gas of volume 300 cm³ at a pressure of 1 atmosphere and temperature of 27°C is compressed to 5 atmospheres and then heated to 127°C at constant pressure. The new volume of the gas would be:

At what temperature is the r.m.s. speed of nitrogen molecules equal to that of hydrogen molecules at 27°C? (A nitrogen molecule is 14 times as massive as a hydrogen molecule.)

Which of the following phenomenon could not be explained by the wave theory of light?

Which of the following could influence the speed of sound in air?

    (A) Frequency of the sound wave

    (B) Temperature of air

    (C) Humidity of air

Of the thermometers given below, the most suitable thermometer to measure the temperature of a drop of liquid is,

The volume expansivity of a metal is equal to:

When one touches a piece of metal in the environment, one feels it to be colder than a piece of wood. Because,

An ideal transformer has 100 windings in the primary and 200 windings in the secondary. The primary is connected to an A.C. supply of 120 V at 10 A. Then the “voltage/current” in the secondary is:

A radioactive nucleus $_Z^A X$ decays by emission of an α-particle followed by a ϒ-ray. The daughter nucleus thus formed has a mass number and atomic number:

Consider the following statements made regarding an object of mass m at a height h from the surface of the earth.

(A) Gravitational force acting on the object does not depend on h.

(B) Gravitational potential energy of the object does not depend on m.

(C) Gravitational potential energy of the object depends on h.

Of the statements: