Questions from College Physics

Q: The electric field is defined as the electric force per unit charge

The electric field is defined as the electric force per unit charge. Explain why the magnetic field cannot be defined as the magnetic force per unit charge.

Q: Centrifuges are commonly used in biological laboratories for the isolation and maintenance

Centrifuges are commonly used in biological laboratories for the isolation and maintenance of cell preparations. For cell separation, the centrifugation conditions are typically 1.0 × 103 rev/min usin...

Q: An electron is moved from point A, where the electric potential

An electron is moved from point A, where the electric potential is VA = −240 V, to point B, where the electric potential is VB = −360 V. What is the change in the electric potential energy?

Q: Two magnifying glasses are labeled with their angular magnifications. Glass A

Two magnifying glasses are labeled with their angular magnifications. Glass A has a magnification of “2×” (M = 2) and glass B has a magnification of 4×. Which has the longer focal length? Explain.

Q: A dc motor is connected to a constant emf of 12.

A dc motor is connected to a constant emf of 12.0 V. The resistance of its windings is 2.0 ΩAt normal operating speed, the motor takes in 6.0 W of electrical power. (a) What is the initial current dr...

Q: A 5.0 kg block of wood is attached to a

A 5.0 kg block of wood is attached to a spring with a spring constant of 150 N/m. The block is free to slide on a horizontal frictionless surface once the spring is stretched and released. A 1.0 kg bl...

Q: In her bag, a photographer is carrying three camera lenses with

In her bag, a photographer is carrying three camera lenses with focal lengths of 400.0 mm, 50.0 mm, and 28.0 mm. Which lens should she use for (a) wide angle shots (a cathedral, taken from the square...

Q: Abductin, an elastic protein found in the ligaments of scallops,

Abductin, an elastic protein found in the ligaments of scallops, has a Young’s modulus of 4.0 MPa. The inner hinge ligament has a cross-sectional area of 0.78 mm2 and a relaxed length of 1.0 mm. When...

Q: A horizontal wire that runs east-west carries a steady current

A horizontal wire that runs east-west carries a steady current to the east. A C-shaped magnet (see Fig. 19.3a) is placed so that the wire runs between the poles, with the north pole above the wire and...

Q: In 1988 the shroud of Turin, a piece of cloth that

In 1988 the shroud of Turin, a piece of cloth that some people believe is the burial cloth of Jesus, was dated using 14C. The measured 14C activity of the cloth was about 0.23 Bq/g. According to this...