A ray of light in water meets a flat sided block of Perspex with an angle of incidence of 55°. The angle of refraction in the Perspex is 47°. If the absolute refractive index of water is 1.33. determine
the refractive index of Perspex​

Which example has gravitational potential energy? a.a horse slowing down from a run b.an apple about to fall from a tree branch c.a bicycle being pedaled down a horizontal path d.beaker sitting on the floor

Explain what happens at the saturation point when adding salt to water at room temperature.

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.