1
JEE Main 2024 (Online) 30th January Morning Shift
+4
-1

A series L.R circuit connected with an ac source $$E=(25 \sin 1000 t) V$$ has a power factor of $$\frac{1}{\sqrt{2}}$$. If the source of emf is changed to $$\mathrm{E}=(20 \sin 2000 \mathrm{t}) \mathrm{V}$$, the new power factor of the circuit will be :

A
$$\frac{1}{\sqrt{3}}$$
B
$$\frac{1}{\sqrt{2}}$$
C
$$\frac{1}{\sqrt{5}}$$
D
$$\frac{1}{\sqrt{7}}$$
2
JEE Main 2024 (Online) 29th January Evening Shift
+4
-1

In an a.c. circuit, voltage and current are given by:

$$V=100 \sin (100 t) V$$ and $$I=100 \sin \left(100 t+\frac{\pi}{3}\right) \mathrm{mA}$$ respectively.

The average power dissipated in one cycle is:

A
5 W
B
25 W
C
2.5 W
D
10 W
3
JEE Main 2024 (Online) 29th January Morning Shift
+4
-1

A capacitor of capacitance $$100 \mu \mathrm{F}$$ is charged to a potential of $$12 \mathrm{~V}$$ and connected to a $$6.4 \mathrm{~mH}$$ inductor to produce oscillations. The maximum current in the circuit would be :

A
2.0 A
B
3.2 A
C
1.5 A
D
1.2 A
4
JEE Main 2024 (Online) 27th January Evening Shift
+4
-1

Primary side of a transformer is connected to $$230 \mathrm{~V}, 50 \mathrm{~Hz}$$ supply. Turns ratio of primary to secondary winding is $$10: 1$$. Load resistance connected to secondary side is $$46 \Omega$$. The power consumed in it is :

A
11.5 W
B
12.5 W
C
10.0 W
D
12.0 W
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