A. Sometimes light is seen first and sometimes sound is heard first
B. The light is seen first and sound is heard afterwards
C. The sound is heard at the same time as the light is seen
D. The light is seen after the sound is heard
A. Helicopter — Brequet
B. Aeroplane — Barthelemy
C. Telescope — Galileo
D. Barometer — Torricelli
A. Increases
B. Decreases
C. Remains unchanged
D. None of these
A. Hygrometer
B. Hydrometer
C. Gravimeter
D. Hypsometer
A. Long-sightedness
B. Short-sightedness
C. Cataract
D. None of these
A. Increase DC voltage
B. Increase or decrease AC voltage
C. Decrease DC voltage
D. Convert DC into AC
A. Sound waves are absorbed
B. There are obstructions to the sound waves
C. Sound waves cannot travel through vaccum
D. The temperature is high near the moon's surface
A. Copper and Tin
B. Copper and Zinc
C. Copper and Nickel
D. Aluminum and Magnesium
A. Fuming of date palms
B. Fermentation of rotten grapes
C. Fermentation of apple cider in the presence of air
D. Dehydration of wine