All of the following substances are crystalline except_____________?

Water is heated in a kettlE. The inside water is heated by convection. A person sitting near the fire receives heat by ________?

A. Conduction
B. Convection
C. Radiation
D. Reflection
E. None of these

A. Cylindrical Lens  
B. Concave Lens
C. Spherical Lens
D. Convex Lens

Astigmatism is a common vision problem caused by an error in the shape of the cornea. With astigmatism, the lens of the eye or the cornea, which is the front surface of the eye, has an irregular curve. This can change the way light passes, or refracts, to your retina. This causes blurry, fuzzy, or distorted vision.
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would. The curved face or faces of a cylindrical lens are sections of a cylinder, and focus the image passing through it into a line parallel to the intersection of the surface of the lens and a plane tangent to it.

What is it called when the Earth is closest to the sun _____________?

A. Aphelion
B. Perihelion
C. Apoapsis
D. Periapsis

At what angle above the horizon must the sun be to create a rainbow?

A. 90 degrees
B. 60 degrees
C. 40 degrees
D. 65 degrees