I will assume here that the well is sufficiently short so that the time the sound takes to come from the bottom of the well to our ear is negligible.
Since the pebble moves by uniformly accelerated motion, the distance it covers is given by
where
is the gravitational acceleration
is the time the pebble takes to reach the bottom of the well
Therefore, the depth of the well is
and the correct answer is B.
1,000 W = 1 kW
100 W = 0.1 kW
(0.1 kW) x (6 h) = 0.6 kWh <=== energy
(0.6 kWh) x (£0.1359/kWh) = £0.0815 <=== cost of it
Answer:Developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete- Niels Bohr
Discovery of energy quanta made him the originator of quantum theory -Max Plank
Formulated the wave equation; stationary and time-dependent Schrödinger equation- Erwin Schrödinger
Best known to the general public for his "mass–energy equivalence formula" ; E = mc^2-B Albert Einstein
Postulated the wave nature of electrons and suggested that all matter has wave properties- Louis de Broglie
Explanation:
All the names mentioned above contributed towards the development of the wave mechanical model of the atom. Their names were matched with their contributions as required by the question.