A mass $$m$$ is attached to two strings as shown in figure. The spring constants of two springs are $$\mathrm{K}_{1}$$ and $$\mathrm{K}_{2}$$. For the frictionless surface, the time period of oscillation of mass $$m$$ is :

Two resistances are given as $$\mathrm{R}_{1}=(10 \pm 0.5) \Omega$$ and $$\mathrm{R}_{2}=(15 \pm 0.5) \Omega$$. The percentage error in the measurement of equivalent resistance when they are connected in parallel is -

For the plane electromagnetic wave given by $$E=E_{0} \sin (\omega t-k x)$$ and $$B=B_{0} \sin (\omega t-k x)$$, the ratio of average electric energy density to average magnetic energy density is

The resistivity $$(\rho)$$ of semiconductor varies with temperature. Which of the following curve represents the correct behaviour :