An automated planetary probe orbiting Saturn's moon Titan detects a uniform beam of far-infrared radiation emitted from a localized hydrothermal region. The total intensity of this radiation beam at the probe's altitude is 4.5×10−5 W m−24.5 \times 10^{-5}\text{ W m}^{-2}4.5×10−5 W m−2 and its spectrum exhibits a peak intensity at a wavelength of 25 μm25\ \mu\text{m}25 μm.
Calculate the energy of a single photon at this peak wavelength.
Estimate the number of such photons incident per second on a flat infrared sensor with an active surface area of 80 cm280\text{ cm}^280 cm2. Assume all incident photons have this peak wavelength.
A planetary scientist models the warming of Titan's surface pools. Estimate the maximum rise in temperature per second of a shallow cylindrical pool of liquid methane with a depth of 0.75 m0.75\text{ m}0.75 m, assuming all radiation incident on the pool's surface is fully absorbed. (Density of liquid methane =420 kg m−3= 420\text{ kg m}^{-3}=420 kg m−3, specific heat capacity of liquid methane =2200 J kg−1 K−1= 2200\text{ J kg}^{-1}\text{ K}^{-1}=2200 J kg−1 K−1)
26 exam-style questions on OCR A A Level Physics Quantum physics, covering Photons, The photoelectric effect, and Wave–particle duality. Each one has a worked solution and a mark scheme showing where the marks go.