The variation of EMF with time for four types of generators is shown in the figures. Which amongst them can be called AC voltage?

 (a) (b) (c) (d)

 1 (a) and (d) 2 (a), (b), (c), and (d) 3 (a) and (b) 4 only (a)

Subtopic: Â AC vs DC |
Â 78%
From NCERT
NEET - 2019
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

An AC ammeter is used to measure the current in a circuit. When a given direct current passes through the circuit, the AC ammeter reads $$6$$ A. When another alternating current passes through the circuit, the AC ammeter reads $$8$$ A. Then the reading of this ammeter if DC and AC flow through the circuit simultaneously is:
1. $$10 \sqrt{2}$$ A
2. $$14$$ A
3. $$10$$ A
4. $$15$$ A

Subtopic: Â AC vs DC |
Â 65%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

In the diagram, two sinusoidal voltages of the same frequency are shown. What is the frequency and the phase relationship between the voltages?

 Frequency in Hz Phase lead of $$N$$ over $$M$$ in radians 1. $$0.4$$ $$-\pi/4$$ 2. $$2.5$$ $$-\pi/2$$ 3. $$2.5$$ $$+\pi/2$$ 4. $$2.5$$ $$-\pi/4$$
Subtopic: Â AC vs DC |
Â 67%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

A direct current of $$5~ A$$ is superimposed on an alternating current $$I=10sin ~\omega t$$ flowing through a wire. The effective value of the resulting current will be:

 1 $$15/2~A$$ 2 $$5 \sqrt{3}~A$$ 3 $$5 \sqrt{5}~A$$ 4 $$15~A$$
Subtopic: Â AC vs DC |
Â 61%
From NCERT
Hints

A generator produces a voltage that is given by $$V = 240\sin(120t)$$, where $$t$$ is in seconds. The frequency and rms voltage are:
 1 $$60$$ Hz and $$240$$ V 2 $$19$$ Hz and $$120$$ V 3 $$19$$ Hz and $$170$$ V 4 $$754$$ Hz and $$70$$ V
Subtopic: Â RMS & Average Values |
Â 83%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

An alternating current is given as $$i = i_1\cos\omega t- i_2 \sin \omega t.$$ The value of rms current is given by:
1. $$\frac{1}{\sqrt{2}}\left(i_1+i_2\right)$$
2. $$\frac{1}{\sqrt{2}}\left(i_i+i_2\right)^2$$
3. $$\frac{1}{\sqrt{2}}\left(i_1^2+i_2^2\right)^{1 / 2}$$
4. $$\frac{1}{2}\left(i_1^2+i_2^2\right)^{1 / 2}$$
Subtopic: Â RMS & Average Values |
Â 80%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The variation of the instantaneous current $$(I)$$ and the instantaneous emf $$(E)$$ in a circuit are shown in the figure. Which of the following statements is correct?

 1 The voltage lags behind the current by $$\frac{\pi}{2}$$. 2 The voltage leads the current by $$\frac{\pi}{2}$$. 3 The voltage and the current are in phase. 4 The voltage leads the current by $$\pi$$.
Subtopic: Â RMS & Average Values |
Â 78%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The time required for a $$50$$ Hz sinusoidal alternating current to change its value from zero to the rms value will be:
1. $$1 . 5 \times 10^{- 2}~\text{s}$$

2. $$2 . 5 \times 10^{- 3}~\text{s}$$

3. $$10^{- 1}~\text{s}$$

4. $$10^{- 6}~\text{s}$$

Subtopic: Â RMS & Average Values |
Â 76%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The rms value of the potential difference $$V$$ shown in the figure is:

 1 $$\dfrac{V_{0}}{\sqrt{3}}$$ 2 $$V_{0}$$ 3 $$\dfrac{V_{0}}{\sqrt{2}}$$ 4 $$\dfrac{V_{0}}{2}$$
Subtopic: Â RMS & Average Values |
Â 74%
From NCERT
AIPMT - 2011
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The output current versus time curve of a rectifier is shown in the figure. The average value of the output current in this case will be:

 1 $$0$$ 2 $$I_0 \over 2$$ 3 $$2I_0 \over \pi$$ 4 $$I_0$$
Subtopic: Â RMS & Average Values |
Â 66%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints