Determine the focal length of a plano-concave lens (refractive index n =1.5) with 24 cm radius of curvature on its curve surface 1)-96 cm
2)-24 cm
3)-48 cm
4)-72 cm

The dot diagram represents the motion of the motorcycle as it moves from left to right

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.

What are the similarities & differences between a thermistor and a light dependent resistor in physics?