[الأمير المدريدي]

The longest wavelength of light that causes electrons to be ejected from the
surface of a copper plate is 243 nm. What is the maximum velocity of the
electrons ejected when light of wavelength 200. Nm shines on a copper plate?
A. 1.48 × 106 m/s
b. 6.22 × 105 m/s
c. 4.67 × 104 m/s
d. 1.97 × 104 m/s
e. 1.34 × 106 m/s

. When photons with a wavelength of 310. Nm strike a magnesium plate, the
maximum velocity of the ejected electrons is 3.45 × 105 m/s. Calculate the
binding energy of electrons to the magnesium surface.
A. 386 kj/mol
b. 419 kj/mol
c. 32.7 kj/mol
d. 321 kj/mol
e. 353 kj/mol

. The electron in a hydrogen atom falls from an excited energy level to the ground
state in two steps, causing the emission of photons with wavelengths of 1870 and
102.5 nm. What is the quantum number of the initial excited energy level from
which the electron falls?
A. 2
b. 3
c. 4
d. 6
e. 8