1
JEE Main 2020 (Online) 6th September Evening Slot
+4
-1
A student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings 5.50 mm, 5.55 mm, 5.45 mm, 5.65 mm. The average of these four readings is 5.5375 mm and the standard deviation of the data is 0.07395 mm. The average diameter
of the pencil should therefore be recorded as :
A
(5.54 $$\pm$$ 0.07) mm
B
(5.5375 $$\pm$$ 0.0740) mm
C
(5.5375 $$\pm$$ 0.0739) mm
D
(5.538 $$\pm$$ 0.074) mm
2
JEE Main 2020 (Online) 6th September Morning Slot
+4
-1
A screw gauge has 50 divisions on its circular scale. The circular scale is 4 units ahead of the pitch scale marking, prior to use. Upon one complete rotation of the circular scale, a displacement of 0.5mm is noticed on the pitch scale. The nature of zero error involved and the least count of the screw gauge, are respectively :
A
Positive, 0.1 mm
B
Positive, 0.1 $$\mu$$m
C
Positive, 10 $$\mu$$m
D
Negative, 2 $$\mu$$m
3
JEE Main 2020 (Online) 5th September Evening Slot
+4
-1
The quantities x = $${1 \over {\sqrt {{\mu _0}{\varepsilon _0}} }}$$, y = $${E \over B}$$ and z = $${l \over {CR}}$$ are
defined where C-capacitance, R-Resistance, l-length, E-Electric field, B-magnetic field and $${{\varepsilon _0}}$$, $${{\mu _0}}$$, - free space permittivity and permeability respectively. Then :
A
Only y and z have the same dimension
B
x, y and z have the same dimension
C
Only x and y have the same dimension
D
Only x and z have the same dimension
4
JEE Main 2020 (Online) 5th September Morning Slot
+4
-1
A physical quantity z depends on four observables
a, b, c and d, as z = $${{{a^2}{b^{{2 \over 3}}}} \over {\sqrt c {d^3}}}$$. The percentages of error in the measurement of a, b, c and d are 2%, 1.5%, 4% and 2.5% respectively. The percentage of error in z is :
A
13.5 %
B
14.5%
C
16.5%
D
12.25%
EXAM MAP
Medical
NEET