The coefficient of performance of a refrigerator is $5$. If the temperature inside the freezer is $-20\,^{\circ}C$,the temperature of the surroundings to which it rejects heat is ....... $^{\circ}C$.

Among the following statements,the incorrect one is:

The mass of oxygen gas occupying a volume of $11.2 \text{ litres}$ at a temperature $27^{\circ}C$ and a pressure of $760 \text{ mm}$ of mercury in kilograms is $[$Molecular weight of oxygen $= 32]$

$y=A e^x+B e^{2 x}+C e^{3 x}$ satisfies the differential equation

Two magnets are held together in a vibration magnetometer and are allowed to oscillate in the earth's magnetic field. With like poles together,$12$ oscillations per minute are made,but for unlike poles together,only $4$ oscillations per minute are executed. The ratio of their magnetic moments is:

Which of the following statements about the Bohr model of the hydrogen atom is false?