Estimating physical quantitiesAQA A-Level Physics: Flashcards

What these 12 flashcards ask

What is the order of magnitude of a quantity?
How do you find the order of magnitude of A × 10ⁿ?
What is the order of magnitude of 5.4×10⁵ J?
What is the diameter of an atom, to the nearest order of magnitude?
What is the diameter of a nucleus, to the nearest order of magnitude?
What is the mass of a typical adult, to the nearest order of magnitude?
What is the mass of a family car, to the nearest order of magnitude?
What is the approximate number of seconds in a year?
What is the density of water, to the nearest order of magnitude?
If two lengths differ by a factor of 10⁵, by what factor do their volumes differ?
What does it mean for two quantities to be 3 orders of magnitude apart?
What steps should an estimate follow?

Exam questions on Estimating physical quantities

A teacher asks a class to estimate the sizes and masses of familiar objects and particles to the nearest order of magnitude.
A nucleus has a diameter of order 10⁻¹⁵ m and an atom has a diameter of order 10⁻¹⁰ m. Estimate how many times larger the volume of the atom is than the volume of its nucleus.2 marks
A student estimates the number of times a human heart beats in a lifetime. Assume a resting heart rate of about 70 beats per minute and a lifetime of about 80 years.
Each heartbeat pumps about 70 cm³ of blood. Estimate the total volume of blood pumped in a lifetime, in m³, to the nearest order of magnitude.2 marks
A classroom is about 10 m long, 8 m wide and 3 m high. The density of air is about 1.2 kg m⁻³, the molar mass of air is about 0.029 kg mol⁻¹ and the Avogadro constant is 6.0×10²³ mol⁻¹.
Estimate the mass of air in the classroom, to the nearest order of magnitude.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).