51.

Once the active medium is excited, the first photons of light are produced by which physical process?
A. Blackbody radiation B. Spontaneous emission
C. Synchrotron radiation D. Planck’s oscillation
Answer and Explanation
Answer:B
Explanation: Spontaneous emission is what you see with most "glow in the dark" toys. You excite the toy by exposing it to bright light, then the toy glows in the dark by spontaneously emitting photons as the excited atoms relax back down to their normal state.
52.

'DTP' computer abbreviation usually means ?
A. Digital Transmission Protocol B. DeskTop Publishing
C. Data Type Programming D. Document Type Processing
Answer and Explanation
Answer:B
Explanation: No answer description available for this question.
53.

The average power (in watts) used by a 20 to 25 inch home color television is...?
A. 70-100 B. 25-50
C. 500-800 D. Over 1000
Answer and Explanation
Answer:A
Explanation: About the same as as the most popular light bulb size.
54.

What does AC and DC stand for in the electrical field?
A. Alternating Current and Direct Current B. A Rock Band from Australia
C. Average Current and Discharged Capacitor D. Atlantic City and District of Columbia
Answer and Explanation
Answer:A
Explanation: Electricity is voltage and current. Voltage is electrical pressure, and current is the flow of charged particles. The difference between alternating current (AC) and direct current (DC) is that the electrons in an AC circuit regularly reverse their direction. In a DC circuit electrons always flow in the same direction.
55.

In which decade was the ARRL founded?
A. 1940s B. 1930s
C. 1920s D. 1910s
Answer and Explanation
Answer:D
Explanation: On April 6, 1914, Hiram Percy Maxim proposed the formation of the American Radio Relay League.