The document discusses the photoelectric effect and how various factors influence photoemission. It notes that: 1) As frequency increases, the photon energy and kinetic energy of emitted electrons increases. The stopping potential also increases with higher frequencies. 2) For a given metal, the saturation current increases with higher light intensities due to more photons and emitted electrons. 3) Different metals have different threshold frequencies above which photoemission occurs, and higher frequencies result in more negative stopping potentials.

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2.  1.as frequency increases,
energy increases.
 2.at particular frequency, work
function of metal is overcome
 & photo emission starts.
 3. this freq. is called as
THRESHOLD /CUTOFF
FREQUENCY./ (Def+ cha.1)
 4. Different metals : Different
threshold frequency
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3.  1.Above threshold
frequency,
 As intensity
increases…no.of photons
/area increases.
 2. so no.of emitted
electrons increases.
 3. so photo current
increases.
 Linearly with intensity.
(cha.2)
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5.  Cha.3
 Kinetic energy of
emitted electrons
will increase linearly
with frequency
 Cha.4: instantanous
process (nano
seconds)
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6.  1.more & more electrons attract
to anode….so photo current
increases.
 2.at perticular anode potential,
all electrons are reached at
anode…so photo current
becomes maximum.
 3.after this, even if potential
increaes…current remains
MAXIMUM & CONSTANT
 called as…
 SATURATION
CURRENT.
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7.  1.without potential difference
also small current will be there
due to kinetic energy of free
electrons so..
 Graph starts above zero
 2. more intensity ..more
photons…more electrons
more saturation current…
 3. intensity will give more
photons but not more
energetic photos. (here cha.3)
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8.  1. negative potential of anode
repel coming electrons.
 So photo current decreases.
 2.at particular negative
potential electrons stop
completely reaching anode.
 So photo current becomes
zero.
 3. such negative potential is
called as
 CUT OFF/STOPPING
POTENTIAL

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9. Frequency
(colour of
light) same
Intensity Saturation
current
Energy of
photon &
so
K.Energy of
electrons
Stopping
potential
for given
metal
Red Dim Low Same Same
Red Bright High Same Same
Red Brighter Higher same Same
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11. Frequency
(colour of
light)
Different
Intensity
(same)
Saturation
current
Energy of
photon &
so
K.Energy of
electrons
Stopping
potential
for given
metal
Red Bright Same Low Negative
(low)
yellow Bright Same High More
negative
(lower)
violet Bright same higher Much more
negative
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13.  1. if frequency increases…
 photon energy will also
increases…
 so K.energy of emitted
electrons will be high.
 .& therefore stopping potential
also increases…
 2. so above threshold
frequency.. As frequency
increases..stopping potential
increases.
 3. at threshold frequency,
stopping potential=zero.
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