1
JEE Main 2021 (Online) 25th July Evening Shift
Numerical
+4
-1
A 16 $$\Omega$$ wire is bend to form a square loop. A 9V supply having internal resistance of 1$$\Omega$$ is connected across one of its sides. The potential drop across the diagonals of the square loop is _______________ $$\times$$ 10$$-$$1 V
2
JEE Main 2021 (Online) 25th July Morning Shift
Numerical
+4
-1
Student A and student B used two screw gauges of equal pitch and 100 equal circular divisions to measure the radius of a given wire. The actual value of the radius of the wire is 0.322 cm. The absolute value of the difference between the final circular scale readings observed by the students A and B is ______________.

[Figure shows position of reference 'O' when jaws of screw gauge are closed]

Given pitch = 0.1 cm.

3
JEE Main 2021 (Online) 22th July Evening Shift
Numerical
+4
-1
Three students S1, S2 and S3 perform an experiment for determining the acceleration due to gravity (g) using a simple pendulum. They use different lengths of pendulum and record time for different number of oscillations. The observations are as shown in the table.

Student
No.
Length of
Pendulum (cm)
No. of
oscillations (n)
Total time for
n oscillations
Time
period (s)
1 64.0 8 128.0 16.0
2 64.0 4 64.0 16.0
3 20.0 4 36.0 9.0

(Least count of length = 0.1 cm and Least count for time = 0.1 s)

If E1, E2 and E3 are the percentage errors in 'g' for students 1, 2 and 3 respectively, then the minimum percentage error is obtained by student no. ______________.
4
JEE Main 2021 (Online) 18th March Evening Shift
Numerical
+4
-1
The radius of a sphere is measured to be (7.50 $$\pm$$ 0.85) cm. Suppose the percentage error in its volume is x.

The value of x, to the nearest x, is __________.
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