Physics Flashcards
7 cards from real Regents practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Physics flashcards as text
A photon has a frequency of 6.0 × 10¹⁴ Hz. What is its energy? (h = 6.63 × 10⁻³⁴ J·s)
Answer: 3.98 × 10⁻¹⁹ J
E = hf = (6.63 × 10⁻³⁴)(6.0 × 10¹⁴) ≈ 3.98 × 10⁻¹⁹ J.
A spring with spring constant k = 200 N/m is compressed 0.05 m. What is the elastic potential energy stored?
Answer: 0.25 J
PE = ½kx² = ½(200)(0.05)² = ½(200)(0.0025) = 0.25 J.
In the photoelectric effect, increasing the intensity of incident light (at constant frequency) causes:
Answer: More electrons to be emitted per second
Greater intensity means more photons per second, each ejecting one electron, so the emission rate increases but individual electron energy does not.
Two resistors of 6 Ω each are connected in parallel. What is the equivalent resistance?
Answer: 3 Ω
For two equal resistors in parallel: R_eq = R/2 = 6/2 = 3 Ω.
A standing wave is formed on a string. The distance between two adjacent nodes is 0.4 m. What is the wavelength?
Answer: 0.8 m
Adjacent nodes are separated by half a wavelength, so λ = 2 × 0.4 = 0.8 m.
Which of the following describes the Doppler effect?
Answer: The change in observed frequency due to relative motion between source and observer
The Doppler effect is the apparent change in frequency when source and observer are moving relative to each other.
A nucleus of carbon-14 undergoes beta-minus decay. The resulting nucleus is:
Answer: Nitrogen-14
In beta-minus decay, a neutron converts to a proton, increasing the atomic number by 1: carbon (Z=6) becomes nitrogen (Z=7), mass number unchanged at 14.