What is a standard candle?
A standard candle is an astronomical object that has a known absolute magnitude (intrinsic brightness). They are extremely important to astronomers since by measuring the apparent magnitude of the object the distance to the source can be determined by using the inverse square law. Examples of such objects are Cepheid variable stars, whose absolute magnitude is proportional to their period of variability and also the Type-1a supernovae, since it is believed that they all have essentially the same peak absolute magnitude.
AS
Related Physics A Level answers
All answers ▸Why is the refractive index of water bigger than that of air?
2 Capacitors (c1 = 500mf) and (c2=300mf), are connected in parallel to a 10v d.c supply. Calculate the total capacitance of the circuit, and hence the total energy stored in the capacitors.
A photon has an energy of 1.0 MeV. Calculate the frequency associated with this photon energy. State an appropriate unit in your answer.
What is the difference between a scalar and a vector quantity?