JEE Main · 2024 · 27 Jan 2024 · Shift 1 · Units & Measurement

Identify the physical quantity that cannot be measured using spherometer :

(A)Radius of curvature of concave surface
(B)Specific rotation of liquids✓ Correct
(C)Thickness of thin plates
(D)Radius of curvature of convex surface

Answer: (B)

Solution

A spherometer measures the radius of curvature of spherical (concave or convex) surfaces and the thickness of thin plates, via the height of a central leg relative to three fixed legs. Specific rotation of liquids is an optical-activity measurement made with a polarimeter, not a spherometer.

JEE Main · 2024 · 27 Jan 2024 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Units & Measurement →

More JEE Main questions on Units & Measurement

If ε, E and t represent the free space permittivity, electric field and time respectively, then the unit of $\frac{εE}{t}$ will be :
JEE Main 2026View solution →
Keeping the significant figures in view, the sum of the physical quantities $52.01 m, 153.2 m$ and 0.123 m is :
JEE Main 2026View solution →
A spherical body of radius $r$ and density $σ$ falls freely through a viscous liquid having density $ρ$ and viscosity $η$ and attains a terminal velocity $v_{0}$ . Estimated maximum error in the quantity $η$ is : (Ignore errors associated with …
JEE Main 2026View solution →
Four persons measure the length of a rod as $20.00 cm$ , $19.75 cm$ , $17.01 cm$ and $18.25 cm$ . The relative error in the measurement of average length of the rod is:
JEE Main 2026View solution →
In a screw gauge, the zero of the circular scale lies 3 divisions above the horizontal pitch line when their metallic studs are brought in contact. Using this instrument thickness of a sheet is measured. If pitch scale reading is 1 mm and the circular scale reading is 51 then the …
JEE Main 2026View solution →
A ball of radius r and density $ρ$ dropped through a viscous liquid of density $σ$ and viscosity $η$ attains its terminal velocity at time t, given by $t = A ρ^{a} r^{b} η^{c} σ^{d}$ , where A is a constant and a, b, c and d are integers. The value of $\frac{b + c}{a + d}$ …
JEE Main 2026View solution →