1
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

The percentage increase in magnetic field $$\mathrm{B}$$ when the space within a current carrying solenoid is filled with a medium of susceptibility 0.004 is

A
0.04
B
4
C
40
D
0.4
2
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

A storage battery of emf $$28.0 \mathrm{~V}$$ and internal resistance $$0.5 \Omega$$ is being charged by a $$140 \mathrm{~V}$$ dc supply using a series resistor of $$27.5 \Omega$$. The terminal voltage of the battery during charging is

A
26V
B
2V
C
5V
D
30V
3
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

A metallic rod of length '$$a$$' is rotated with an angular frequency of $$0.2 \mathrm{~rads}^{-1}$$ about an axis normal to the rod passing through its one end. A constant and uniform magnetic field of '$$\mathrm{B}$$' T parallel to the axis exists everywhere. The emf developed across the ends of the rod is

A
$$\frac{\mathrm{Ba}^2}{10}$$
B
$$\frac{\mathrm{Ba}^2}{5}$$
C
$$\frac{\mathrm{Ba}^2}{50}$$
D
$$\frac{\mathrm{Ba}^2}{2}$$
4
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

A semiconductor $$\mathrm{X}$$ is made by doping silicon with phosphorous. A second semiconductor $$\mathrm{Y}$$ is made by doping silicon with aluminium. The two are joined by a suitable technique to form a $$\mathrm{p}$$-$$\mathrm{n}$$ junction and is connected to a battery such that $$\mathrm{Y}$$ is joined to negative of the battery and $$\mathrm{X}$$ to the positive of the battery. Which of the following statements is correct?

A
Potential barrier of the junction is zero and current is due to minority carriers
B
Potential barrier of the junction is raised and current is due to majority carriers
C
Potential barrier of the junction is raised and current is due to minority carriers
D
Potential barrier of the junction is lowered and current is due to minority carriers
EXAM MAP