The given electrical network is equivalent to:
   

1.	\(\mathrm{OR}\) gate	2.	\(\mathrm{NOR}\) gate
3.	\(\mathrm{NOT}\) gate	4.	\(\mathrm{AND}\) gate

Which one of the following represents the forward bias diode?

1.
2.
3.
4.

A long solenoid of diameter \(0.1\) m has \(2 \times 10^4\) turns per meter. At the center of the solenoid, a coil of \(100\) turns and radius \(0.01\) m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at a constant rate to \(0\) A from \(4\) A in \(0.05\) s. If the resistance of the coil is \(10\pi^2~\Omega\) then the total charge flowing through the coil during this time is:
1. \(16~\mu \text{C}\)
2. \(32~\mu \text{C}\)
3. \(16\pi~\mu \text{C}\)
4. \(32\pi~\mu \text{C}\)

Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time \(t_1\). On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time \(t_2\). The time taken by her to walk upon the moving escalator will be:
1. \(\frac{t_1t_2}{t_2-t_1}\)
2. \(\frac{t_1t_2}{t_2+t_1}\)
3. \(t_1-t_2\)
4. \(\frac{t_1+t_2}{2}\)

A beam of light from a source \(L\) is incident normally on a plane mirror fixed at a certain distance \(x\) from the source. The beam is reflected back as a spot on a scale placed just above the source \(L\). When the mirror is rotated through a small angle \(\theta,\) the spot of the light is found to move through a distance \(y\) on the scale. The angle \(\theta\) is given by:
1. \(\frac{y}{x}\)
2. \(\frac{x}{2y}\)
3. \(\frac{x}{y}\)
4. \(\frac{y}{2x}\)

If \(\phi_1\) and \(\phi_2\) are the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip \(\phi\) is given by:
1. \(cos^2{\phi}=cos^2{\phi_1}+cos^2{\phi_2}\)
2. \(sec^2{\phi}=sec^2{\phi_1}+sec^2{\phi_2}\)
3. \(tan^2{\phi}=tan^2{\phi_1}+tan^2{\phi_2}\)
4. \(cot^2{\phi}=cot^2{\phi_1}+cot^2{\phi_2}\)

Two cars moving in opposite directions approach each other at speeds of 22 m/s and 16.5 m/s, respectively. The driver of the first car blows a horn with a frequency of 400 Hz. The frequency heard by the driver of the second car is [assume velocity of sound to be 340 m/s]:

1. 361 Hz

2. 411 Hz

3. 448 Hz

4. 350 Hz
 

A massless and inextensible string connects two blocks \(\mathrm{A}\) and \(\mathrm{B}\) of masses \(3m\) and \(m,\) respectively. The whole system is suspended by a massless spring, as shown in the figure. The magnitudes of acceleration of \(\mathrm{A}\) and \(\mathrm{B}\) immediately after the string is cut, are respectively:
         

A thin prism having refracting angle \(10^\circ\) is made of glass of a refractive index \(1.42\). This prism is combined with another thin prism of glass with a refractive index \(1.7\). This combination produces dispersion without deviation. The refracting angle of the second prism should be:
1. \(6^{\circ}\)
2. \(8^{\circ}\)
3. \(10^{\circ}\)
4. \(4^{\circ}\)