${O^{ + + }},\;{C^ + },\;H{e^{ + + }}$ and ${H^ + }$ ions are projected on the photographic plate with same velocity in a mass spectrograph. Which one will strike farthest
${O^{ + + }}$
${C^ + }$
$H{e^{ + + }}$
$H_2^ + $
A metal plate gets heated, when cathode rays strike against, it due to
Particle nature and wave nature of electromagnetic waves and electrons can be shown by
A stick of $1 \,m$ is moving with velocity of $2.7 \times {10^8}m{s^{ - 1}}$. ........... $m$ is the apparent length of the stick $(c = 3 \times {10^8}m{s^{ - 1}})$
Answer the following questions:
$(a)$ guarks inside protons and neutrons are thought to carry fractional charges $[(+2 / 3) e ; (-1 / 3) e] .$ Why do they not show up in Millikan's oil-drop experiment?
$(b)$ What is so special about the combination $e / m ?$ Why do we not simply talk of $e$ and $m$ separately?
$(c)$ Why should gases be insulators at ordinary pressures and start conducting at very low pressures?
$(d)$ Every metal has a definite work function. Why do all photoelectrons not come out with the same energy if incident radiation is monochromatic? Why is there an energy distribution of photoelectrons?
$(e)$ The energy and momentum of an electron are related to the frequency and wavelength of the assoctated matter wave by the relations:
$E=h v, p=\frac{h}{\lambda}$
But while the value of $\lambda$ is physically significant, the value of $v$ (and therefore, the value of the phase speed $v \lambda$ ) has no physical significance. Why?
In $1897$, J.J.Thomson invented which particle ?