Explanation:
Power of electric kettle, P = 1 kW
Voltage, V = 220 V
(a) Electric power is given by the formula as follows :
R is resistance
(b) When connected to a 220 V supply, it takes 3 minutes for the water in the kettle to reach boiling point.
Energy supplied is given by :
P is power,
Answer: Rock candy is candy made of large sugar crystals. To make rock candy, a supersaturated solution of sugar in water is created and left undisturbed for a few days. The driving force behind crystallization is supersaturation.
Lower resistivity means higher conductivity: among these materials, the best conductor is silver, therefore it must be the material with lowest resistivity among those. We can also have a look at the value of resistivity of the different materials listed in the problem, to check our answer. The resistivities of the materials are the following:
Wood:
Salt water:
Silver:
Lead:
<span>We see that the material with lowest resistivity among those is silver, therefore the correct answer is silver.</span>
Answer:
Changes in the object's momentum (answer D)
Explanation:
A net force will cause an object to change its velocity, and that will affect the object's momentum, which is defined by the product of the object's mass times its velocity.
So, select the last option (D) in the given list.
Answer:
a. The angular frequency is doubled.
e. The period is reduced to one-half of what it was.
Explanation:
Angular frequency is given as;
ω = 2πf
when the frequency is doubled
Thus, the angular frequency will be doubled.
Amplitude in simple harmonic motion is the maximum displacement.
Frequency is related to period in simple harmonic motion as given in the equation below;
when the frequency is doubled;
Thus, the period will be reduced to one-half of what it was.
