Q. Find the equivalent resistance between points $A$ and $B$.

Q. $\left(i\right)$ Where should an object be placed so that a real and inverted image of the same size as the object is obtained using a convex lens?
$\left(ii\right)$ Draw a ray diagram to show the formation of the image specified in the part $\left(i\right)$.

Q. Draw a simplified diagram of a lemon crusher, indicating of load and effort.

Q. Explain the motion of a planet around the sun in a circular path.

Q. $\left(i\right)$ Why is a cathode ray tube evacuated to a low pressure?
$\left(ii\right)$ What happens if the negative potential is changed on a grid?

Q. Rajan exerts a force of $150N$ in pulling a cart at a constant speed of $10m/s$. Calculate the power exerted.

Q. State the energy changes in the following while in use:
$\left(i\right)$ Burning of candle.
$\left(ii\right)$ A steam engine.

Q. $\left(i\right)$ Name the physical quantity measured in terms of horse power.
$\left(ii\right)$ A nut is opened by a wrench of length $20cm$. If the least force required is $2N$, find the moment of force needed to loosen the nut.
$\left(iii\right)$ Explain briefly why the work done by a fielder when he takes a catch in a cricket match is negative.

Q. Give two similarities between an A.C. generator and a D.C. motor.

Q. $\left(i\right)$ On what factor does the position of the centre of gravity of a body depend?
$\left(ii\right)$ What is the S.I.unit of the moment of force?

Q. When a body is placed on a table top, it exerts a force equal to its weight downwards on the table top but does not move or fall.
$\left(i\right)$ Name the force exerted by the table top.
$\left(ii\right)$ What is the direction of the force?

Q. In the diagram $A,B,C,D$ are four pendulums suspended from the same elastic string $PQ$. The length of $A$ and $C$ are equal to each other while the length of pendulum $B$ is smaller than that of $D$. Pendulum $A$ is set into a mode of vibrations.
$\left(i\right)$ Name the type of vibrations taking place in pendulums $B$ and $D$?
$\left(ii\right)$ What is the state of pendulum $C$?
$\left(iii\right)$ State the reason for the type of vibrations in pendulums $B$ and $C$.

Q. A person standing between two vertical cliffs and $480m$ from the nearest cliff shouts. He hears the first echo after $3s$ and the second echo $2s$ later.
Calculate:
$\left(i\right)$ The speed of sound.
$\left(ii\right)$ The distance of the other cliff from the person.

Q. $\left(i\right)$ Draw a graph between displacement and the time for a body executing free vibrations.
$\left(ii\right)$ Where can a body execute free vibrations?

Q. Rishi is surprised when he sees water boiling at ${115}^{o}C$ in a container. Give reasons as to why water can boil at the above temperature.

Q. The speed of light in glass is $2\times {10}^5$ $km/s$. What is the refractive index of glass?

Q. $\left(i\right)$ What happens to the resistivity of semi-conductors with the increase of temperature?
$\left(ii\right)$ For a fuse, higher the current rating ________ is the fuse wire. (Thicker / Thinner)

Q. $\left(i\right)$ Why does the Sun appear red at sunrise?
$\left(ii\right)$ Name the subjective property of light related to its wavelength.

Q. $\left(i\right)$ Name the device used to increase the voltage at a generating station.
$\left(ii\right)$ At what frequency is A.C. supplied to residential houses?
$\left(iii\right)$ Name the wire in a household electrical circuit to which the switch is connected.

Q. Name the factors affecting the turning effect of a body.

Q. $\left(i\right)$ Define equilibrium.
$\left(ii\right)$ In a beam balance when the beam is balanced in a horizontal position, it is in .................. equilibrium.

Q. $\left(i\right)$ Name one factor that affects the lateral displacement of light as it passes through a rectangular glass slab.
$\left(ii\right)$ On reversing the direction of the current in a wire, the magnetic field produced by it gets ___________

Q. $\left(i\right)$ State the safe limit of sound level in terms of decibel for human hearing.
$\left(ii\right)$ Name the characteristic of sound in relation to its waveform.

Q. Jatin puts a pencil into a glass container having water and is surprised to see the pencil in a different state.
$\left(i\right)$ What change is observed in the appearance of the pencil?
$\left(ii\right)$ Name the phenomenon responsible for the change.
$\left(iii\right)$ Draw a ray diagram showing how the eye sees the pencil?

Q. How is work done by a force measured when the force:
$\left(i\right)$ is in the direction of displacement.
$\left(ii\right)$ is at an angle to the direction of displacement.

Q. $\left(i\right)$ Give the expression for mechanical advantage of an inclined plane in terms of the length of an inclined plane.
$\left(ii\right)$ Name a common device where a gear train is used.

Q. A block and tackle system has V.R $=5$
$\left(i\right)$ Draw a neat labelled diagram of a system indicating the direction of its load and effort.
$\left(ii\right)$ Rohan exerts a pull of $150$ $kgf$. What is the maximum load he can raise with this pulley system if its efficiency is $75$%?

Q. $\left(i\right)$ Name the high energetic invisible electromagnetic waves which help in the study of the structure of crystals.
$\left(ii\right)$ State an additional use of the waves mentioned in part $\left(i\right)$.

Q. $\left(i\right)$ Why does a current-carrying freely suspended solenoid rest along a particular direction?
$\left(ii\right)$ State the direction in which it rests.

Q. $\left(i\right)$ A scissor is a _________ multiplier.
$\left(ii\right)$ $1$ $kWh=$_________$J$.