In a hall-effect experiment, a current of 3.7 a sent lengthwise through a conductor 1.5 cm wide, 4.0 cm long, and 12 μm thick produces a transverse (across the width) hall potential difference of 78 μv when a magnetic field of 0.76 t is passed perpendicularly through the thickness of the conductor.

a) find the drift velocity of the charge carriers and the number density of charge carriers.
b) show on a diagram the polarity of the hall potential difference.

Lymphocytes known as blastocysts make antibodies that fight infection. select the best answer from the choices provided t f

1. what is the relationship between wavelength and the penetrating power of an electromagnetic wave? a) the penetrating power has no relationship to the wavelength. b) the penetrating power increases as the wavelength increases. c) the penetrating power decreases as the wavelength increases. d) the penetrating power decreases as the wavelength decreases. 2. as ice melts and turns into water, the speed of sound through the material would most likely do what? justify your answer. a) the speed would not change because the material is always water. b) the speed of sound would increase because the density of water is less than that of ice. c) the speed of sound would increase because energy is added to ice in order to make it melt. d) the speed of sound would decrease because sound travels faster through solids than liquids. 3.which of these waves need a medium to travel through? a) sound b) x-rays c) infrared rays d) visible light

An alarm clock has a current of 4.5 amps and a resistance of 3.2 ohms. what is the voltage in the circuit? a.1.4 volts b.0.71 volts c.14 volts d.46 volts