KCET 2018

In the series $L-C-R$ circuit, the power dissipation is through

In Karnataka, the normal domestic power supply AC is $220 \mathrm{~V}, 50 \mathrm{~Hz}$. Here, 220 V and 50 Hz refer to

A 100 W bulb is connected to an AC source of $220 \mathrm{~V}, 50 \mathrm{~Hz}$. Then, the current flowing through the bulb is

Which of the following, represents the variation of inductive reactance $\left(X_L\right)$ with the frequency of voltage sources $(v)$ ?

The energy equivalent to a substance of mass 1 g is

The half-life of tritium is 12.5 years. What mass of tritium of initial mass 64 mg will remain undecayed after 50 years?

The total energy of an electron revolving in the second orbit of hydrogen atom is

The period of revolution of an electron in the ground state of hydrogen atom is $T$. The period of revolution of the electron in the first excited state is

Two capacitors of $3 \mu \mathrm{~F}$ and $6 \mu \mathrm{~F}$ are connected in series and a potential difference of 900 V is applied across the combination. They are then disconnected and reconnected in parallel. The potential difference ac...

For the arrangement of capacitors as shown in the circuit, the effective capacitance between the points $A$ and $B$ is (capacitance of each capacitor is $4 \mu \mathrm{~F}$ )

The radius of the Earth is 6400 km . If the height of an antenna is 500 m , then its range is

The effective resistance between $P$ and $Q$ for the following network is

If the last band on the carbon resistor is absent, then the tolerance is

The $I-V$ graphs for two different electrical appliances $P$ and $Q$ are shown in the diagram: If $R_P$ and $R_Q$ be the resistances of the devices, then

Two cells of internal resistances $r_1$ and $r_2$ and of same emf are connected in series, across a resistor of resistance $R$. If the terminal potential difference across the cells of internal resistance $r_1$ is zero, then the value of $R...

The resistance $R=\frac{V}{I}$, where $V=(100 \pm 5) \mathrm{V}$ and $I=(10 \pm 0.2) \mathrm{A}$. The percentage error in $R$ is

Five identical resistors each of resistance $R=1500 \Omega$ are connected to a 300 V battery as shown in the circuit. The reading of the ideal ammeter $A$ is

Ohm's law is applicable to

A proton and an $\alpha$-particle are accelerated through the same potential difference $V$. The ratio of their de-Broglie wavelength is

The maximum kinetic energy of emitted photoelectrons depends on

The number of photons falling per second on a completely darkened plate to produce a force of $6.62 \times 10^{-5} \mathrm{~N}$ is $n$. If the wavelength of the light falling is $5 \times 10^{-7} \mathrm{~m}$, then $n=$ $\ldots \ldots \ldot...

Two wires $A$ and $B$ are stretched by the same load. If the area of cross-section of wire $A$ is double that of $B$, then the stress on $B$ is

A step-up transformer operates on a 230 V "ne and a load current of 2 A . The ratio of primary and secondary windings is $1: 25$. Then, the current in the primary is

The magnetic flux linked with a coil varies as $\phi=3 t^2+4 t+9$. The magnitude of the emf induced at $t=2 \mathrm{~s}$ is

The work done to move a charge on an equipotential surface is

The magnitude of point charge due to which the electric field 30 cm away has the magnitude $2 \mathrm{NC}^{-1}$ will be

A mass of 1 kg carrying a charge of 2 C is accelerated through a potential of 1 V . The velocity acquired by it is

The force of repulsion between two identical positive charges when kept with a separation $r$ in air is $F$. Half the gap between the two charges is filled by a dielectric slab of dielectric constant $=4$. Then, the new force of repulsion b...

The pressure at the bottom of a liquid tank is not proportional to the

A space station is at a height equal to the radius of the Earth. If ' $v_E$ ' is the escape velocity on the surface of the Earth, the same on the space station is $\qquad$ times $v_E$.

Which of the following graphs correctly represents the variation of $g$ on the Earth?

A mass $m$ on the surface of the Earth is shifted to a target equal to the radius of the Earth. If $R$ is the radius and $M$ is the mass of the Earth, then work done in this process is

Pressure of an ideal gas is increased by keeping temperature constant. The kinetic energy of molecules

A cup of tea cools from $65.5^{\circ} \mathrm{C}$ to $62.5^{\circ} \mathrm{C}$ in 1 min in a room at $22.5^{\circ} \mathrm{C}$. How long will it take to cool from $46.5^{\circ} \mathrm{C}$ to $40.5^{\circ} \mathrm{C}$ in the same room?

A Carnot engine takes 300 calories of heat from a source at 500 K and rejects 150 calories of heat to the sink. The temperature of the sink is

A block rests on a rough inclined plane making an angle of $30^{\circ}$ with the horizontal, The coefficient of static friction between the block and the plane is 0.8 . If the frictional force on the block is 10 N , the mass of the block is...

A man weighing 60 kg is in a lift moving down with an acceleration of $1.8 \mathrm{~ms}^{-2}$. The force exerted by the floor on him is

The strength of the Earth's magnetic field is

Needles $N_1, N_2$ and $N_3$ are made of a ferromagnetic, a paramagnetic and adiamagnetic substance, respectively. A magnet when brought close to them will

A jet plane having a wing-span of 25 m is travelling horizontally towards East with a speed of $3600 \mathrm{~km} / \mathrm{hr}$. If the Earth's magnetic field at the location is $4 \times 10^{-4} \mathrm{~T}$ and the angle of dip is $30^{\...

A particle shows distance-time curve as shown in the figure. The maximum instantaneous velocity of the particle is around the point.

The correct Biot-Savart law in vector form is

A charge $q$ is accelerated through a potential difference $V$. It is then passed normally through a uniform magnetic field, where it moves in a circle of radius $r$. The potential difference required to move it in a circle of radius $2 r$ ...

A cyclotron's oscillator frequency is 10 MHz and the operating magnetic field is 0.66 T . If the radius of its dees is 60 cm , then the kinetic energy of the proton beam produced by the accelerator is

An electron is moving in a circle of radius $r$ in a uniform magnetic field $B$. Suddenly, the field is reduced to $\frac{B}{2}$. The radius of the circular path now becomes

An object is placed at a distance of 20 cm from the pole of a concave mirror of focal length 10 cm . The distance of the image formed is

An object is placed at the principal focus of a convex mirror. The image will be at

A candle placed 25 cm from a lens forms an image on a screen placed 75 cm on the other side of the lens. The focal length and type of the lens should be

Moment of inertia of a body about two perpendicular axes $X$ and $Y$ in the plane of lamina are $20 \mathrm{~kg}-\mathrm{m}^2$ and $25 \mathrm{~kg}-\mathrm{m}^2$, respectively. Its moment of inertia about an axis perpendicular to the plane ...

The density of electron-hole pair in a pure germanium is $3 \times 10^{16} \mathrm{~m}^{-3}$ at room temperature. On doping with aluminium, the hole density increases to $4.5 \times 10^{22} \mathrm{~m}^{-3}$. Now, the electron density (in $...