Scientific Instruments — Set 2
Physics · वैज्ञानिक उपकरण · Questions 11–20 of 70
What does a 'Pyrometer' measure?
Correct Answer: C. Very high temperatures
The correct answer is 'Very high temperatures'. A pyrometer is a non-contact thermometer used to measure the temperature of distant or extremely hot surfaces. It works by detecting the thermal radiation emitted by the object. These are essential for monitoring molten metals in furnaces.
Which device is used for measuring the growth of plants?
Correct Answer: B. Auxanometer
An auxanometer measures the increase in length or volume of plant parts over time. It often uses a pulley system and a pointer to amplify small growth increments. Sir J.C. Bose famously invented the Crescograph for similar high-precision measurements.
Which instrument is used to measure very small current?
Correct Answer: D. Galvanometer
A galvanometer is a sensitive instrument that detects and measures small electrical currents. It works by the deflection of a needle caused by a magnetic field. It can be converted into an ammeter or voltmeter by adding resistors.
Which instrument is used to determine the altitude of an aircraft?
Correct Answer: A. Altimeter
An altimeter determines the height of an aircraft above a fixed level, usually sea level. Most aircraft use barometric altimeters that calculate height based on atmospheric pressure changes. Radar altimeters are also used for more precise ground-clearance readings.
What is the function of a 'Periscope'?
Correct Answer: D. To see objects above sea level from a submarine
A periscope allows a viewer to see objects that are not in a direct line of sight using mirrors or prisms. It is commonly used in submarines to observe the surface while remaining underwater. The simplest version consists of two mirrors held at a 45-degree angle.
Which instrument is used to measure the purity of gold?
Correct Answer: D. Karatmeter
A karatmeter uses X-ray fluorescence technology to non-destructively determine the purity of gold. It provides the gold content in Karats or percentage values within seconds. This tool is standard in jewelry shops for verifying metal authenticity.
A 'Chronometer' is used to measure which of the following?
Correct Answer: D. Precise time
A chronometer is a highly accurate timepiece that can function even under changing temperatures or motion. It was historically vital for marine navigation to determine longitude at sea. John Harrison is credited with inventing the first practical marine chronometer.
Which instrument is used for measuring the curvature of spherical surfaces?
Correct Answer: B. Spherometer
A spherometer consists of a central screw and three fixed legs used to measure the radius of curvature. It is extensively used in optics to check the thickness of lenses and mirrors. The device can measure very small linear distances with high accuracy.
Which device is used to measure the intensity of sound?
Correct Answer: B. Audiometer
An audiometer is an instrument used to evaluate a person's hearing sensitivity and sound intensity. It produces tones of different frequencies to determine the softest sound a person can hear. Results are typically plotted on a graph called an audiogram.
Which instrument is used for recording the sound under water?
Correct Answer: B. Hydrophone
A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. It converts acoustic energy into electrical energy for analysis. These devices are crucial for marine biology research and submarine tracking.