Tag: physics

Questions Related to physics

The maximum frequency at which an op-amp may operate depends on the _____.

the operational amplifier (op-amp) electronics physics properties of an ideal op-amp

  1. bandwidth (BW)

  2. slew rate (SR)

  3. unity-gain bandwidth

  4. All of the above

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Correct Option: D

An operational amplifier is a _____ gain and _____ bandwidth differential amplifier.

the operational amplifier (op-amp) electronics physics properties of an ideal op-amp

  1. very low, narrow

  2. low, wide

  3. medium, narrow

  4. very high, wide

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Correct Option: D

Pick out the correct option from the below for an opamp:

the operational amplifier (op-amp) electronics physics properties of an ideal op-amp

  1. output impedance= 75 ohms, input impedance = 1 M ohm and bandwidth = 5kHz

  2. output impedance= 75 ohms, input impedance = 1000 M ohm and bandwidth = 5kHz

  3. output impedance= 750 ohms, input impedance = 1 M ohm and bandwidth = 5kHz

  4. output impedance= 750 ohms, input impedance = 1 M ohm and bandwidth = 500 MHz

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Correct Option: B

The output of a particular Op-amp increases 8V in 12s. The slew rate is .

the operational amplifier (op-amp) electronics physics properties of an ideal op-amp

  1. $90 V/\mu s$

  2. $0.67 V/\mu s$

  3. $1.5 V/\mu s$

  4. None of these

Show answer
Correct Option: B
Explanation:

Given,

$\triangle V=8V$
$\triangle t=12 s$
To find, Slew rate$=?$
Slew rate is defined as the voltage change in $\triangle V$ with respect to changing time $\triangle t$
$\therefore$ Slew rate $=\cfrac{\triangle V}{\triangle t}$
$\Rightarrow $ Slew rate$=\cfrac{8V}{12s}$
$\Rightarrow$ Slew rate$=0.666$
$\Rightarrow$ Slew Rate$\simeq 0.67$

 Which among the following amplifier circuit exhibit the output voltage in the form of phase inversion?

the operational amplifier (op-amp) electronics physics properties of an ideal op-amp

  1. Adder

  2. Substractor

  3. Integrator

  4. Differentiator

Show answer
Correct Option: A
Explanation:

In any adder circuitry of Op-amp, the output voltage must be equivalent to the summation of all input voltages where each input voltage is a multiple of constant gain factor. This circuit is usually more similar to inverting scalar type of amplifier with an exception of possessing more than one input. Therefore, output voltage of adder or summer Op-amp is phase inverted.

Referring to subtractor, integrator and differentiator amplifiers, the output voltage of subtractor deals with the difference between two input signals, while integrator generates its output voltage in terms of integral of input voltage whereas the output voltage of differentiator is proportional to change in input in accordance to time.

Which among the following are the major responsible reasons for the cause of 'Slew Rate'?

the operational amplifier (op-amp) electronics physics properties of an ideal op-amp

  1. Current limiting

  2. Saturation of internal stages due to application of high frequency & amplitude signal

  3. Both a & b

  4. None of the above

Show answer
Correct Option: C

Which among the following is also used as a buffer or an isolation amplifier?

the operational amplifier (op-amp) electronics physics properties of an ideal op-amp

  1. Inverting amplifier

  2. Non-inverting amplifier

  3. Unity Follower

  4. Emitter Follower

Show answer
Correct Option: C
Explanation:

Unity Follower circuit provides buffering or can be also used as an isolation amplifier which has a provision to obtain a gain at unity despite the requisite of any phase reversal. Emitter follower circuit is also semantic to unity follower only with an exception of gain which is in very much proximity of being absolutely equal to 1 (unity level). 

Unity Follower is supposed to be used as buffer since it becomes quite feasible to transfer the input voltage in the form of output voltage along with the prevention of load resistance from loading down to input source simultaneously. This becomes possible because the value of input resistance tends to infinity & output resistance equals to zero.

An electronic oscillator is:

the operational amplifier (op-amp) electronics physics properties of an ideal op-amp

  1. just like an alternator

  2. an amplifier with feedback

  3. nothing but an amplifer

  4. a.c. to d.c. energy converter

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Correct Option: B

A force acts on a $30$gm particle in such a way that the position of the particle as a function of time is given by $x=3t-4t^2+t^3$, where x is in metres and t is in seconds. The work done during the first $4$ second is?

physics simple harmonic motion representing shm with circular motion shm as projection of circular motion simple harmonic motion (shm) as a projection of uniform circular motion

  1. $2.88$J

  2. $450$mJ

  3. $490$mJ

  4. $530$mJ

Show answer
Correct Option: A
Explanation:

$M=20gm=0.020kg$

$x=3t-4t²+t³m$
$v=dx/dt=3-8t+3t²m/s$
$a=dv/dt=-8+6tm/s²$
$Force=ma=0.120t-0.160N$
$Workdone=dW=Fdx=F\ast \frac { dx }{ dt } \ast dt=(0.120t-0.160)\ast (3-8t+3t²)dt=0.360t³-1.440t²+1.640t-0.480$
$W=0.090t⁴-0.490t³+0.82t²-0.480t=2.88J$

A wheel of radius $1$ meters rolls forward half a revolution on a horizontal ground. The magnitude of the displacement of the point of the wheel initially in contact with the ground is:

physics simple harmonic motion representing shm with circular motion shm as projection of circular motion simple harmonic motion (shm) as a projection of uniform circular motion

  1. $2 \pi$

  2. $\sqrt 2 \pi$

  3. $\sqrt {{\pi ^2} + 4} $

  4. $\pi$

Show answer
Correct Option: C
Explanation:
Let fro $A$ to $B$, where complete half a rotation.
we have,
$PQ=\alpha =$ half circumference $=\pi \ m$
and $P' Q=$ diameter $=2\ m$
so we have displacement of $P$
$x=|PP;|=\sqrt {PQ^2 +P; Q^2}$ (Pythagoras theorem)
$\Rightarrow \ x=\sqrt {\pi^2 +4}m$