Which form of energy is primarily converted into electrical energy in a hydroelectric power plant?
A. Potential energy
B. Kinetic energy
C. Mechanical energy
D. Thermal energy
B. Kinetic energy
According to Einstein's theory of special relativity, which of these remains constant for all observers?
A. Speed of the observer
B. Speed of light in a vacuum
C. Passage of time
D. Energy of a photon
B. Speed of light in a vacuum
A wave travels at 340 m/s. If its frequency increases from 170 Hz to 340 Hz, what is the new wavelength?
A. 2.0 m
B. 1.0 m
C. 0.5 m
D. 0.25 m
New wavelength = speed / new frequency = 340 / 680 = 0.5 m
These substances control the rates of chemical reactions... A: Reactants, B: Catalysts, C: Isotopes, D: Cathodes
What is B: Catalysts. Catalysts are substances that control the rates of chemical reactions.
Two long, parallel wires carry equal currents in opposite directions. At a point exactly midway between them, the net magnetic field is:
A. Zero, because the fields cancel each other
B. Maximum, due to constructive interference
C. Directed perpendicular to the plane containing the wires
D. Non-zero, and directed parallel to the wires
C. Directed perpendicular to the plane containing the wires
Which of the following elements has the largest atomic radius?
A. Sodium (Na)
B. Potassium (K)
C. Chlorine (Cl)
D. Oxygen (O)
B. Potassium (K)
A photon with energy 6.63 × 10⁻¹⁹ J hits a metal surface. Given Planck's constant h = 6.63 × 10⁻³⁴ Js, what is the frequency of the photon?
A. 1.00 × 10¹⁵ Hz
B. 1.50 × 10¹⁴ Hz
C. 6.63 × 10¹⁵ Hz
D. 3.31 × 10¹⁴ Hz
A. 1.00 × 10¹⁵ Hz