121. The disadvantage of fluorescent lamps as compared to GLS lamps is
(A) noise in choke
(B) stroboscope effect
(C) high cost
(D) all of the above.
122. In case of a fluorescent lamp if only the ends of the lamp remain lighted it indicates
(A) a short circuited starter
(B) a defective choke
(C) a defective lube
(D) defective wiring.
123. Blinking of a fluorescent tube may be due to
(A) low circuit voltage
(B) low ballast rating
(C) low temperature
(D) any of the above.
124. Radio interference generally results due to
(A) GLS lamps
(B) Halogen lamps
(C) Fluorescent lamps
(D) Sodium lamps.
125. A fluorescent tube can be operated on
(A) AC only
(B) DC only
(C) Both AC as well as DC.
126. The ignition voltage for sodium lamps is
(A) 100 to 150 volts .
(B) 200 to 220 volts
(C) 400 to 440 volts
(D) 400 to 600 volts.
127. A leak transformer is provided with
(A) frosted GLS lamps
(B) high wattage GLS lamps
(C) fluorescent lamps
(D) sodium lamps
128. Leak transformer in sodium lamps initially provides
(A) low voltage
(B) high current
(C) high voltage
(D) none of the above.
129. The color of sodium lamp is
(A) blue
(B) yellow
(C) red
(D) white.
130. Sodium lamps are used for
(A) reading rooms
(B) street lights
(C) auditoria
(D) libraries
131. The average life of sodium lamps is around
(A) 1000 hours
(B) 2500 hours
(C) 6000 hours
(D) 12000 hours.
132. High pressure mercury vapor light contains
(A) yellow color
(B) bluish white color
(C) red color
(D) white color.
133. The average life high pressure mercury vapor lamps is
(A) 500 hours
(B) 1000 hours
(C) 9000 hours
(D) 20,000 hours.
134. High pressure mercury vapor lamps are generally used in
(A) factories
(B) railway yards
(C) shopping centers
(D) all of the above.
135. A substance which changes its electrical resistance when illuminated by light is called
(A) photovoltaic
(B) photoelectric
(C) photo-conductive
(D) none of the above.