A hockey player hits the ball at an angle of $$37^{\circ}$$ from the horizontal with an initial speed of $$40 \mathrm{~m} / \mathrm{s}$$ (a right angled triangle with one of the angle is $$37^{\circ}$$ and their sides in the ratio of $$6: 8: 10$$). Assume that the ball is in a vertical plane. The time at which the ball reaches the highest point of its path is
What feature of the infrared waves make it useful for the haze photography?
A spring of force constant $$k$$ is cut into lengths of ratio $$1:3:4$$. They are connected in series and the new force constant is $$\mathrm{k}$$'. Then they are connected in parallel and force constant is $$\mathrm{k}$$''. Then $$\mathrm{k}^{\prime}: \mathrm{k}^{\prime \prime}$$ is
A light having wavelength $$6400^{\circ} \mathrm{A}$$ is incident normally on a slit of width $$2 \mathrm{~mm}$$. Then the linear width of the central maximum on the screen kept $$2 \mathrm{~m}$$ from the slit is :