If the atomic number of an element is 8 and its mass number is 20, how many neutrons are in the atom's nucleus?

Two flat rectangular mirrors are set edge to edge and placed perpendicular to a flat nonreflecting surface. The edges of the two mirrors meet at a 30° angle. A light ray that approaches mirror 1 is parallel to mirror 2.

A 100.0 resistor, a 50.0 resistor, and a 40.0 resistor are connected in parallel and placed across a 12.0 V battery. ( a. What is the equivalent resistance of the parallel circuit? Incorrect: Your answer is incorrect. ( b.

Why is it impossible to build a machine that produces more energy than it uses?

Seven times the number of quarters in a coin collection is the same as three times the number of quarters increased by 20. How many quarters in the collection

What is the effect of the perimeter conductor in the Dipole of Like Charges? How does it affect the shape of the electric field?

A. Which skill related fitness component is your strongest and weakest?

A 100 N box is placed on an inclined plane that makes a 30° angle with the horizontal. Calculate the component of gravitational force that acts down the inclined plane. A. 25 N B. 50 N C. 87 N D. 100 N

Approximately how many kelvins are equal to 60 c? a. 289k b. 323k c. 333k d. 413k

What are two ways to change velocity?

What is the main optical element of a refracting telescope?