A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of $15 ms^{-1}.$Then, the frequency of sound that the observer hears in the echo reflected from the cliff is (Take velocity of sound in air = 330$ms^{-1}$)

A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to 8 × 10⁻⁴ J by the end of the second revolution after the beginning of the motion?

An air column, closed at one end and open at the other, resonates with a tuning fork when the smallest length of the column is 50 cm. The next larger length of the column resonating with the same tuning fork is

To get output 1 for the following circuit, the correct choice for the input is A, B, C.

A gas is compressed isothermally to half of its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then

Consider the molecules $CH_4, NH_3$ and $H_2O.$ Which of the given statements is false ?

In the reaction $H-C \equiv H \xrightarrow[2. CH_3 CH_2Br]{1. NaNH_2/liq. NH_3} X \xrightarrow[2. CH_3CH_2Br]{1. NaNH_2/liq. NH_3} Y.$ X and Y are

Among the following, the correct order of acidity is

The rate of a first-order reaction is $0.04 \,$mol L$^{-1}$s$^{-1}$ at $10 \,$s and $0.03 \,$mol L$^{-1}$s$^{-1}$ at $20 \,$s$$ after initiation of the reaction. The half-life period of the reaction is (in seconds).

Which one of the following characteristics is associated with adsorption?

A system of rotating crops with legume or grass pasture to improve soil structure and fertility is called

Mitochondria and chloroplast are (a) semi-autonomous organelles (b) formed by division of pre-existing organelles and they contain DNA but lack protein synthesizing machinery. Which one of the following options is correct?

In context of amniocentesis, which of the following statement is incorrect?

In a chloroplast the highest number of protons are found in

Photosensitive compound in human eye is made up of