{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# PHYSICS7 - FORM 0[1 The work function of copper is 4.7 eV...

This preview shows pages 1–2. Sign up to view the full content.

FORM 0 [1] The work function of copper is 4 . 7 eV. Electrons are emitted in the photoelectric effect if the wavelength of the incident light is [A] more than the threshold wavelength of 1 . 14 × 10 15 nm. [B] less than the threshold wavelength of 1 . 14 × 10 15 nm. [C] less than the threshold wavelength of 264 nm. [D] less than the threshold wavelength of 1 . 14 × 10 15 Hz. [E] more than the threshold wavelength of 264 nm. [2] A 1 W monochromatic light source emits orange light of wavelength 620 nm. About how many photons per second are emitted by the source? [A] 3 . 1 × 10 18 [B] 6 . 2 × 10 18 [C] 2 [D] 3 . 2 × 10 - 19 [E] 0.5 [3] Electrons are accelerated with a voltage of 60 , 000 V. The accelerated electrons hit a metal target. The most energetic photons emitted are [A] γ rays with an energy of 60,000 electron Volts. [B] X rays with an energy of 30,000 electron Volts [C] X rays with an energy of 60,000 electron Volts [D] X rays with an energy of 60,000 Joules [4] Two stars are at rest with respect to each other. Observers in the stars observe an astronaut fly from one star to the other with a speed of v = 0 . 9 c in a time of 20 years. How long did the trip last as measured by the astronaut?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 3

PHYSICS7 - FORM 0[1 The work function of copper is 4.7 eV...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online