A ball is projected from the ground with a speed 15 ms^$$-$$1 at an angle $$\theta$$ with horizontal so that its range and maximum height are equal,
then 'tan $$\theta$$' will be equal to :

The maximum error in the measurement of resistance, current and time for which current flows in an electrical circuit are $$1 \%, 2 \%$$ and $$3 \%$$ respectively. The maximum percentage error in the detection of the dissipated heat will be :

Hydrogen atom from excited state comes to the ground state by emitting a photon of wavelength $$\lambda$$. The value of principal quantum number '$$n$$' of the excited state will be : ($$\mathrm{R}:$$ Rydberg constant)

A particle is moving in a straight line such that its velocity is increasing at 5 ms^$$-$$1 per meter. The acceleration of the particle is _____________ ms^$$-$$2 at a point where its velocity is 20 ms^$$-$$1.