Consider a laser pointer and cellphone, as shown below. 8.1 State the type of electromagnetic radiation that is emitted by the: 8.1.1 Laser pointer (1) 8.1.2 Cellphone (1) 8.2 A laser pointer uses red light photons with a wavelength of 620 nm. 8.2.1 Define the term photon. (2) 8.2.2 Calculate the energy of a red … Read more
Dolphins communicate through the emission and reception of sounds. A young dolphin was separated from its mother and started whistling at a frequency of 130 kHz to call her. The speed of sound in seawater is 1480m∙s-1. 7.1 Explain the term ultrasound. (2) 7.2 Calculate the wavelength of the young dolphin’s whistle. (4) 7.3 Another … Read more
Two girls, standing at opposite ends of a rope, each makes a pulse of the same speed. Pulse A, with an amplitude of 4 cm, moves to the right and pulse B, with an amplitude of -6 cm, moves to the left. The pulses meet at point C. 6.1 State the phenomenon observed when the … Read more