Top answers

Explain why excited atoms only emit certain frequencies of radiation after an electron collides with the atom

Radiation is emitted via photons2) Photon energy is governed by the equation E = hc/wavelength, where h = the Planck constant and c = the speed of light. Both h and c are constants3) Electrons have discrete ...
MH
Answered by Michael H. • Physics tutor
6814 Views

I do 400J of work compressing a gas, but I maintain the same temperature. What is the delta U, Q and W in this case?

U = 0Q = -400W = -400
HC
Answered by Helen C. • Physics tutor
2686 Views

A trolley of mass 0.75kg is running along a frictionless track at a constant speed of 0.7ms-1, as the trolley passes below a mass of 0.5kg the mass drops a short vertical distance onto the trolley. Calculate the new velocity of the trolley and mass.

Momentum = mass x velocityInitial momentum = 0.75 x 0.7 =0.525kgms-1Momentum is assumed conserved so final momentum = 0.525kgms-1So final mass = 0.5+0.75 = 1.25kgSo final velocity = 0.525/1.25Final velocity ...
AM
Answered by Alexander M. • Physics tutor
2784 Views

A person has a suitcase with wheels. The person pulls the suitcase with a horizontal force of 13 N for 110 m. Calculate the work done on the suitcase by the person (3 marks).

Work done = force x distance moved Work done = 13 N x 110 m Work done = 1430 J
JT
Answered by Jasmine T. • Physics tutor
5350 Views

What velocity should your boat have if you want to cross a 72m wide river in 6s by the shortest distance, with a 5 m/s downstream current?

Key physics concepts: Velocity vectors, Distance/speed/time relations Key mathematical concepts: Trigonometry, Pythagorean triples, Vector addition/subtraction.Recall that velocity is a vector quantity, and ...
Answered by • Physics tutor
2435 Views