1
COMEDK 2020
MCQ (Single Correct Answer)
+1
-0

Point out the right statements about the validity of Kirchhoff’s junction rule,

A
it is based on conservation of charge.
B
outgoing currents add up and are equal to incoming currents at a junction.
C
bending or reorienting the wire does not change the validity of Kirchhoff's junction rule.
D
All of the above.
2
COMEDK 2020
MCQ (Single Correct Answer)
+1
-0

Four particles each of the mass m are placed at the corners of a square of side length $$l$$. The radius of gyration of the system about an axis perpendicular to the square and passing through its centre is

A
$$\frac{l}{\sqrt2}$$
B
$$\frac{l}{2}$$
C
$$l$$
D
$$\sqrt2l$$
3
COMEDK 2020
MCQ (Single Correct Answer)
+1
-0

A steel wire of length 4.7 m and cross-sectional area $$3.0\times10^{-5}$$ m$$^2$$ stretches by the same amount as a copper wire of length 3.5 m and cross-sectional area of $$4.0\times10^{-5}~\mathrm{m^2}$$ under a given load. What is the ratio of Young's modulus of steel to that of copper?

A
1.8 : 1
B
2.8 : 1
C
3.8 : 1
D
4.8 : 1
4
COMEDK 2020
MCQ (Single Correct Answer)
+1
-0

The masses of 200 g and 300 g are attached to the 20 cm and 70 cm marks of a light meter rod, respectively. The moment of inertia of the system about an axis passing through 50 cm mark is

A
0.15 kg m$$^2$$
B
0.036 kg m$$^2$$
C
0.3 kg m$$^2$$
D
Zero
EXAM MAP