The equation $\beta = \frac{Q_2}{Q_1 - Q_2}$ is true or false?

The temperatures inside and outside of a refrigerator are $260 \ K$ and $315 \ K$ respectively. Assuming that the refrigerator cycle is reversible,calculate the heat delivered to the surroundings for every joule of work done. (in $.73$)

$A$ refrigerator consumes an average $35 \ W$ power to operate between temperatures $-10^{\circ}C$ and $25^{\circ}C$. If there is no loss of energy,how much average heat per second does it transfer? (in $J/s$)

Why does the coefficient of performance of a refrigerator become infinity?

If the door of a refrigerator is kept open,then which of the following is true?

Can the coefficient of performance of a refrigerator be increased by increasing the mass of the working substance?