A mass \(m\) attached to free end of a spring executes SHM with a period of \(1\; s\). If the mass is increased by \(3\; kg\) the period of oscillation increases by one second, the value of mass \(m\) is \(..............kg\).

The balancing length for a cell is \(560 \;\mathrm{cm}\) in a potentiometer experiment. When an external resistance of \(10 \;\Omega\) is connected in parallel to the cell, the balancing length changes by \(60\; \mathrm{cm} .\) If the internal resistance of the cell is \(\frac{\mathrm{N}}{10} \;\Omega,\) where \(\mathrm{N}\) is an integer then value of \(\mathrm{N}\) is

Given below are two statements : \(Statement\) \(I\) : Most of the mass of the atom and all its positive charge are concentrated in a tiny nucleus and the electrons revolve around it, is Rutherford's model. \(Statement\) \(II\) : An atom is a spherical cloud of positive charges with electrons embedded in it, is a special case of Rutherford's model. In the light of the above statements, choose the most appropriate from the options given below.

A force \(\overrightarrow{\mathrm{F}}=2 \hat{i}+\mathrm{b} \hat{j}+\hat{k}\) is applied on a particle and it undergoes a displacement \(\hat{i}-2 \hat{j}-\hat{k}\). What will be the value of \(b\), if work done on the particle is zero.

A collimated beam of light of diameter 2 mm is propagating along x -axis. The beam is required to be expanded in a collimated beam of diameter 14 mm using a system of two convex lenses. If first lens has focal length 40 mm , then the focal length of second lens is _________ mm.

An electric toaster has resistance of \(60\  \Omega\) at room temperature \(\left(27^{\circ} \mathrm{C}\right)\). The toaster is connected to a \(220 \mathrm{~V}\) supply. If the current flowing through it reaches \(2.75 \mathrm{~A}\), the temperature attained by toaster is around _______. (if \(\alpha=2 \times 10^{-4} /{ }^{\circ} \mathrm{C}\) )

The velocity of sound in a gas. in which two wavelengths \(4.08\,m\) and \(4.16\,m\) produce \(40\) beats in \(12\,s\), will be ..............\(ms ^{-1}\)