Una switches on a faint ultraviolet lamp pointed at a clean zinc plate. The lamp is so dim it barely lights the plate at all. The first electrons leave the zinc the instant the light arrives.
Below a metal's minimum frequency, light ejects nothing, however strong it is. This lesson measures the other side: light above the minimum, made as weak as the lamp allows. The question is how long the first electron takes.
There is no delay: the first electrons leave as soon as the light reaches the metal.
Making the light very dim does not create a delay.
Faint ultraviolet light on zinc ejects electrons with no delay, even though it delivers very little energy each second.
However dim the lamp, the start is instant.
Below the minimum frequency the light never ejects an electron; above it, the light ejects electrons at once.
Blue light can eject electrons from a clean potassium plate. Vasco turns the blue lamp down until it is barely visible, then switches it on. When do the first electrons leave?
The blue light's frequency is above potassium's minimum for ejection.
Above the minimum, light ejects electrons immediately, even when it is very dim.
Dimness lowers the energy delivered each second, but it does not delay the start.
The first electrons leave the potassium the instant the light arrives.
Xiomara points two ultraviolet lamps at one zinc plate: a strong one and a faint one, both above zinc's minimum frequency. She switches them on one at a time and watches for the first ejected electron. Which lamp shows a delay?
Above the minimum frequency, ejection is immediate.
The strong lamp ejects electrons the instant it lights the plate.
The faint lamp also ejects electrons the instant it lights the plate.
Neither lamp shows a delay; both begin ejecting at once.
Faint ultraviolet light, above zinc's minimum frequency for ejection, switches on over a clean zinc plate. When do the first electrons leave the zinc?
Una says: 'Even very dim light ejects electrons from zinc with no delay, as long as its frequency is above zinc's minimum.' Is Una correct?
One lamp is below zinc's minimum frequency and very bright. Another is above the minimum and very dim. Both point at one zinc plate. Which lamp ejects electrons first?
Light above a metal's minimum frequency shines on the metal at very low intensity. Which statement describes the start of ejection?
A faint violet lamp lights a clean sodium plate. Violet light is above sodium's minimum frequency for ejection. The lamp switches on at exactly noon. When does the sodium eject its first electrons?
For light shining on zinc, which pair of statements is correct?