An electromagnetic wave of wavelength $’\lambda ‘$ is incident on a photosensitive surface of negligible work function. If ‘m’ mass of photoelectron emitted from the surface has de-Broglie wavelength $\lambda_d$, then:
A cup of coffee cools from $90^{\circ}$C to $80^{\circ}$C in t minutes when the room temperature is $20^{\circ}$C. The time taken by a similar cup of coffee to cool from $80^{\circ}$C to $60^{\circ}$C at the same room temperature $20^{\circ}$C is:
The number of photons per second on an average emitted by the source of monochromatic light of wavelength 600 nm, when it delivers the power of $3.3 \times 10^{-3}$ watt will be: ($h=6.6\times 10^{-34}$Js)
A particle moving in a circle of radius R with a uniform speed takes time T to complete one revolution. If this particle were projected with the same speed at an angle ‘$\theta $’ to the horizontal, the maximum height attained by it equals 4R. The angle of projection ‘$\theta $’ is then given by:
(1) $\theta = {\cos ^{ – 1}}\sqrt {\frac{{g{T^2}}}{{{\pi ^2}R}}} $
(2) $\theta = {\cos ^{ – 1}}\sqrt {\frac{{{\pi ^2}R}}{{g{T^2}}}} $
(3) $\theta = {\sin ^{ – 1}}\sqrt {\frac{{{\pi ^2}R}}{{g{T^2}}}} $
(4) $\theta = {\sin ^{ – 1}}\sqrt {\frac{{2g{T^2}}}{{{\pi ^2}R}}} $ Continue reading A particle moving in a circle of radius R ….→
The resistance $R=\frac {V}{I}$, where $V=(50\pm 2) V$ and $I=(20 \pm 0.2 ) A $. The percentage error in R is ‘x’ %. The value of ‘x’ to the nearest integer is _ _ _ _ . Continue reading $R=\frac {V}{I}$
Q: After meals you wash your hands and due to non-availability of towel you shake your hands to remove the water as much as possible. What makes water remove in this process? Continue reading Hand Washing ~ Q & A→
“The laws of motion dictate that a pebble thrown upwards and a planet orbiting a star are both governed by the same principles, reminding us that the universe is interconnected and bound by a set of fundamental rules.”
