In series RLC resonator, if the self inductance and capacitance become double, the new resonant frequency (f2) and new quality factor (Q2) will be : (f1 = original resonant frequency, Q1 = original quality factor)

To increase the resonant frequency in series LCR circuit,

When you walk through a metal detector carrying a metal object in your pocket, it raises an alarm. This phenomenon works on :

In a series $$LR$$ circuit $$X_L=R$$ and power factor of the circuit is $$P_1$$. When capacitor with capacitance $$C$$ such that $$X_L=X_C$$ is put in series, the power factor becomes $$P_2$$. The ratio $$\frac{P_1}{P_2}$$ is:

A direct current of $$4\mathrm{A}$$ and an alternating current of peak value $$4\mathrm{A}$$ flow through resistance of $$3\Omega$$ and $$2\Omega$$ respectively. The ratio of heat produced in the two resistances in same interval of time will be :

A series LCR circuit has $$\mathrm{L}=0.01\mathrm{H},\mathrm{R}=10\Omega$$ and $$\mathrm{C}=1\mu \mathrm{F}$$ and it is connected to ac voltage of amplitude $$\left({\mathrm{V}}_{\mathrm{m}}\right)50\mathrm{V}$$. At frequency $$60\%$$ lower than resonant frequency, the amplitude of current will be approximately :

The equation of current in a purely inductive circuit is $$5\sin \left(49\pi t-30^{\circ }\right)$$. If the inductance is $$30\mathrm{mH}$$ then the equation for the voltage across the inductor, will be : $$\{$$ Let $$\pi =\frac{22}{7}\}$$

A transformer operating at primary voltage $$8\mathrm{kV}$$ and secondary voltage $$160\mathrm{V}$$ serves a load of $$80\mathrm{kW}$$. Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be

An alternating emf $$\mathrm{E}=440\sin 100\pi \mathrm{t}$$ is applied to a circuit containing an inductance of $$\frac{\sqrt{2}}{\pi }\mathrm{H}$$. If an a.c. ammeter is connected in the circuit, its reading will be :

A coil of inductance 1 H and resistance $$100\Omega$$ is connected to a battery of 6 V. Determine approximately : (a) The time elapsed before the current acquires half of its steady - state value. (b) The energy stored in the magnetic field associated with the coil at an instant 15 ms after the circuit is switched on. (Given $$\ln 2=0.693,{\mathrm{e}}^{-3/2}=0.25$$)

A circuit element $$\mathrm{X}$$ when connected to an a.c. supply of peak voltage $$100\mathrm{V}$$ gives a peak current of $$5\mathrm{A}$$ which is in phase with the voltage. A second element $$\mathrm{Y}$$ when connected to the same a.c. supply also gives the same value of peak current which lags behind the voltage by $$\frac{\pi }{2}$$. If $$\mathrm{X}$$ and $$\mathrm{Y}$$ are connected in series to the same supply, what will be the rms value of the current in ampere?

Only 2% of the optical source frequency is the available channel bandwidth for an optical communicating system operating at 1000 nm. If an audio signal requires a bandwidth of 8 kHz, how many channels can be accommodated for transmission :

The TV transmission tower at a particular station has a height of 125 m. For doubling the coverage of its range, the height of the tower should be increased by

Amplitude modulated wave is represented by $$V_{AM}=10[1+0.4\cos (2\pi \times 10^{4}t)]\cos (2\pi \times 10^{7}t)$$. The total bandwidth of the amplitude modulated wave is :

Match List-I with List-II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} List-I List-II (A) Television signal (I) 03 KHz (B) Radio signal (II) 20 KHz (C) High Quality Music (III) 02 MHz (D) Human speech (IV) 06 MHz

We do not transmit low frequency signal to long distances because- (a) The size of the antenna should be comparable to signal wavelength which is unreal solution for a signal of longer wavelength. (b) Effective power radiated by a long wavelength baseband signal would be high. (c) We want to avoid mixing up signals transmitted by different transmitter simultaneously. (d) Low frequency signal can be sent to long distances by superimposing with a high frequency wave as well. Therefore, the most suitable option will be :

Choose the correct statement for amplitude modulation :

A sinusoidal wave y(t) = 40sin(10 $$\times$$ 106 $$\pi$$t) is amplitude modulated by another sinusoidal wave x(t) = 20sin (1000 $$\pi$$t). The amplitude of minimum frequency component of modulated signal is :

Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-0lax{text-align:left;vertical-align:top} List - I List -II A. Facsimile I. Static Document Image B. Guided media Channel II. Local Broadcast Radio C. Frequency Modulation III. Rectangular wave D. Digital Signal IV. Optical Fiber Choose the correct answer from the following options:

A signal of 100 THz frequency can be transmitted with maximum efficiency by :