NCEA Level 3 Physics Modern Physics Equations

X-rays of a frequency 1.05 x 10¹⁹ Hz can be used to form an image of a bone. What is the energy of an X-ray photon?

• 6.96 x 10^-15 J

• 6.96 x 10⁵³ J

• 6.31 x 10^-53 J

• 1.58x 10⁵² J

Americium-241 found in smoke detectors undergoes alpha decay; Am -> Np + He + g . The rest mass of Np = 3.9360161 x 10^-25 kg, rest mass of Am = 4.0025778 x 10^-25 kg, rest mass of He = 0.0664604 x 10^-25 kg. Work out the energy released in joules.

• 1.013 x 10^-25 kg

• 1.013 x 10^-29 kg

• 3.039 x 10^-21 J

• 9.12 x 10^-13 J

Calculate the wavelength of the light emitted when an electron falls from an energy level of - 6.06 x 10^-20 J to an energy level of - 8.73 x 10^-20 J.

• 2.67 x 10^-20 m

• 7.45 x 10^-6 m

• 4.03 x 10¹³ m

• 1.21 x 10²² m

Calculate the energy associated with an electron which has a mass of 9.1 x 10^-31 kg, if all of its mass could be converted to energy.

• 1.01 x 10^-47 J

• 3.04 x 10^-39 J

• 2.73 x 10^-22 J

• 8.2 x 10^-14 J

An electron of a hydrogen atom drops from an energy state of – 1.36 x 10^-19 J to an energy state of –5.44 x 10^-19 J. What is the wavelength of the emitted photon (and for a bonus point: what part of the electromagnetic spectrum is it in)?

• 488 mm

• 48 nm

• 488 nm

• 4800 nm

The mass of an alpha particle is about 6.644 x 10^-27 kg. Calculate the binding energy of an alpha particle if the four nucleons separately mass 6.695 x 10^-27 kg.

• 5.1 x 10^-29 J

• 1.53 x 10^-20 J

• 4.6 x 10^-12 J

• 6.02 x 10^-9 J

Blue light of frequency 7 x 10¹⁴ Hz is shone on a metal surface. The metal has a threshold frequency of 3 x 10¹⁴ Hz. Calculate the maximum kinetic energy of the ejected electrons.

• 4 x 10¹⁴ J

• 7 x 10¹⁴ J

• 2.1 x 10^-19 J

• 2.65 x 10^-19 J

What is the energy of a photon of yellow light with a wavelength in a vacuum of 5.9 x 10 ^–7 m?

• 5.08 x 10¹⁵ J

• 3.37 x 10^-19 J

• 1.01 x 10^-10 J

• 3.37 x 10⁴⁹ J