SATHEE: Science Scientific Instruments

Science Scientific Instruments

(For RRB CBT-1 & CBT-2 Science Section)

Instrument	Measures / Detects	Unit / Use	1-liner Hook
Barometer	Atmospheric pressure	mm or hPa	“BARO = BARometric pressure”
Altimeter	Height above sea-level	feet / m	“ALTitude-meter”
Ammeter	Electric current	Ampere	“AMpere-meter”
Voltmeter	Potential difference	Volt	Connected in parallel
Odometer	Distance travelled by vehicle	km	“ODO = road kilo-meters”
Hygrometer	Humidity	% RH	“HYGRO = HygROscopic water vapour”
Seismograph	Earthquake waves	Richter scale	“SEISMO = earthquake graph”
Galvanometer	Small electric current	μA	Converted to ammeter by shunt
Lactometer	Purity of milk	degree L	LACTose check
Sphygmomanometer	Blood pressure	mmHg	“SPHYGMO = pulse manometer”

Instrument	Works on / Key Fact	Memory Peg
Spectrometer	Light wavelength	“SPECtrum-meter”
Calorimeter	Heat exchange	CALORie count
Colorimeter	Concentration of coloured solution	COLOR intensity
pH-meter	H⁺ ion activity	0-14 scale, 7 = neutral
Ultrasonoscope	Ultrasound imaging	2-15 MHz frequency
Electroscope	Detect electric charge	Gold-leaf divergence
Manometer	Gas pressure	U-tube liquid height
Dynamo	Converts mech → elec energy	Faraday’s principle
Microscope	1500× max (light)	Resolution ∝ 1/λ
Telescope	Reflecting type → Newtonian	Objective mirror

B.A.V.O.D.H.S.G.L.S.
(Baro, Alti, Volt, Odo, Dynamometer, Hygro, Seismo, Galvano, Sphygmo) – first-letter of each RRB favourite instrument.
“Volt-Parallel, Amp-Series” – voltmeter parallel, ammeter series.
“Left Galvano-Right Dynamo” – left-hand rule for motor, right-hand for dynamo.

🔍 10 Likely RRB MCQs (click to expand)

Which instrument measures atmospheric pressure?
A) Hygrometer B) Barometer C) Altimeter D) Manometer
Ans: B
Sphygmomanometer is used to measure:
A) Blood sugar B) Blood pressure C) Heart beat D) Lung volume
Ans: B
The device that converts mechanical energy into electrical energy is:
A) Motor B) Dynamo C) Galvanometer D) Transformer
Ans: B
A lactometer checks the purity of:
A) Water B) Petrol C) Milk D) Honey
Ans: C
Richter scale is associated with:
A) Rain B) Earthquake C) Wind D) Temperature
Ans: B
Which is connected in parallel in a circuit?
A) Ammeter B) Wattmeter C) Voltmeter D) Galvanometer
Ans: C
The normal pH of human blood is:
A) 6.8 B) 7.0 C) 7.4 D) 8.0
Ans: C
Ultrasonoscope uses sound waves of frequency:
A) 20-200 Hz B) 2-15 MHz C) 20 kHz D) 1 GHz
Ans: B
Gold-leaf electroscope detects:
A) Current B) Charge C) Voltage D) Resistance
Ans: B
Maximum magnification of a light microscope is close to:
A) 100× B) 500× C) 1500× D) 10 000×
Ans: C

Glance table → read mnemonics aloud → solve 10 MCQs in <5 min.
All the best – may your score barometer rise!