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Taking into account of the significant figures, what is the value of $9.99 \text{ m} - 0.0099 \text{ m}$?
Rain is falling vertically downward with a speed of $35 \text{ m/s}$. The wind starts blowing after some time with a speed of $12 \text{ m/s}$ in the east to the west direction. The direction in which a boy standing at the place should hold his umbrella is:
The figure shows a logic circuit with two inputs $A$ and $B$ and the output $C$. The voltage waveforms across $A$, $B$ and $C$ are as given. The logic circuit gate is:
Two amplifiers of voltage gain $20$ each, are cascaded in series. If $0.01\text{ V}$ a.c. input signal is applied across the first amplifier, the output a.c. signal of the second amplifier in volts is:
A ray of light traveling in a transparent medium of refractive index $\mu$ falls on a surface separating the medium from the air at an angle of incidence of $45^{\circ}$. For which of the following values of $\mu$ can the ray undergo total internal reflection?
A point object is placed at a distance of 60 cm from a convex lens of focal length 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a distance of:
An object is mounted on a wall. Its image of equal size is to be obtained on a parallel wall with the help of a convex lens placed between these walls. The lens is kept at distance x in front of the second wall. The required focal length of the lens will be:
In the combination of the following gates, the output Y can be written in terms of inputs A and B as:
A beam of light is incident vertically on a glass slab of thickness 1 cm, and refractive index 1.5. A fraction A is reflected from the front surface while another fraction B enters the slab and emerges after reflection from the back surface. The time delay between them is:
A horizontal ray of light is incident on a right-angled prism with a prism angle of $6^{\circ}$. If the refractive index of the material of the prism is 1.5, then the angle of emergence will be:
For the logic circuit shown, the truth table is:
A p-n photodiode is made of a material with a band gap of $2.0\text{ eV}$. The minimum frequency of the radiation that can be absorbed by the material is nearly:
C and Si both have the same lattice structure, having 4 bonding electrons in each. However, C is an insulator whereas Si is an intrinsic semiconductor. This is because:
A transistor is operated in common-emitter configuration at $V_c = 2\text{ V}$ such that a change in the base current from $100\, \mu\text{A}$ to $200\, \mu\text{A}$ produces a change in the collector current from $5\text{ mA}$ to $10\text{ mA}$. The current gain is:
The motion of planets in the solar system is an example of the conservation of:
The venturi-meter works on
An oil drop of 12 excess electrons is held stationary under a constant electric field of $2.55 \times 10^4$ N/C. The density of the oil is $1.26 \text{ g/cm}^3$. The radius of the drop is:
Pure $\text{Si}$ at $500\text{ K}$ has an equal number of electron ($n_e$) and hole ($n_h$) concentration of $1.5 \times 10^{16} \text{ m}^{-3}$. Doping by indium increases the hole concentration $n_h$ to $4.5 \times 10^{22} \text{ m}^{-3}$. The doped semiconductor is of:
In the circuit shown in the figure, the input voltage $V_i$ is 20 V, $V_{BE} = 0$, and $V_{CE} = 0$. The values of $I_B$, $I_C$ and $\beta$ are given by:
For which one of the following, Bohr model is not valid ?