Physics · General Science · NDA

An infinite combination of resistors, each having resistance $R = 4 \Omega$, is given below. What is the net resistance between the points A and B? (Each resistance is of equal value, $R = 4 \Omega$)

An electric circuit is given below. $V_1 = 1 V$ and Resistance $R = 1000 \Omega$.

The current through the resistance $R$ is very close to $1$ mA and the voltage across point A and B, $V_{AB} = 1 V$. Now the circuit is changed to :

where value of $V_2 = 5 V$. The internal resistances of both the batteries are $0.1 \Omega$. The current through the resistance $R$ is about :

If the current through an electrical machine running on direct current is $15 A$ and the machine runs for $10$ minutes, the charge that passes through the machine during this time is:

Which one of the following is the best shape of a solid metal rod to form the top end of a lightning conductor?

Which of the following forces is/are fundamental in nature?

1. Gravitational force

2. Electromagnetic forces

3. Strong and weak nuclear forces

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A spherical shell of outer radius R and inner radius R/2 contains a solid sphere of radius R/2 (see figure). The density of the material of the solid sphere is ρ and that of the shell is ρ/2. What is the average mass density of the larger sphere thus formed?

The human eye is like a camera that has a lens with :

A uniform meter scale of mass 0.24 kg is made of steel. It is kept on two wedges, W₁ and W₂, in a horizontal position. W₁ is at a distance of 0.2 m from one of its ends, while W₂ is at a distance of 0.4 m from the other end. If the force on the scale is N₁ due to W₁ and N₂ due to W₂, then : (take g = 10.0 m s⁻²)

Escape speed from the Earth is close to 11.2 km s⁻¹. On another planet whose radius is half of the Earth's radius and whose mass density is four times that of the Earth, the escape speed in km s⁻¹ will be close to :

Which one of the following does not apply to sound waves in fluids?

A ball of 0.1 kg mass is dropped on a hard floor from a height of 0.45 m and rises to a height of 0.2 m. If it was in touch with the floor for 0.1 s, the net force it applied on the floor while bouncing is : (take the gravitational acceleration g = 10 m s⁻²)

Which one of the following statements regarding simple pendulum is correct?

Simple pendulum has a time period independent of amplitude:

Which one of the following about different frictional forces is correct?

A metallic bob X of mass m is released from position A. It collides elastically with another identical bob Y placed at rest at position B on a horizontal frictionless table. The angle AOB is 30°.

How high does the bob X rise immediately after the collision?

Consider the two statements given below:

Statement-1 : Infrared waves are also called heat waves.

Statement-2 : Water molecules readily absorb infrared waves.

Select the correct answer using the code given below :

If the block P as shown in the figure below were to be at rest, what should the magnitude of force F be?

Of the following, which does not belong to a nuclear reactor?

Consider the following electric circuit :

The current in the above electric circuit is :

A microscope may be a combination of :

For a human eye, where u is the distance of an object from the eye, f is the focal length of the lens and v is the distance of image from the eye, which is the correct schematic graph?

Which of the following statements with regard to the phenomenon of the primary rainbow formation by water droplets is/are correct?

1. It involves refraction and one internal reflection of sunlight.

2. It involves refraction of sunlight only.

3. It is formed as the inner bow.

4. It may involve more than one internal reflection as well as refraction of sunlight.

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Which one of the following scientists mentioned that an electron in an atom could revolve in certain stable orbits without the emission of radiant energy?

LIGO experiment confirmed one of the predictions of :

A block of mass 2 kg, moving with the initial speed of 3 m/s comes to rest on a rough horizontal surface after travelling a distance of 3 m. The magnitude of the frictional force is :

Which one of the following is primarily responsible for conduction of current in a metal?

Which of the following statements are correct about the electrical resistance and resistivity of a wire?

1. Both quantities depend on the area of cross-section of the wire

2. Both depend on the temperature

3. Resistance of the wire is directly proportional to the resistivity of the wire

4. Resistivity of the wire is directly proportional to the length of the
wire

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An iron nail sinks in water whereas an iron ship floats. Which of the following statements is correct in this regard?

1. Average density of ship is greater than that of the water

2. Average density of iron nail is greater than that of the water

3. Average density of the ship is less than that of the water

4. Average density of the ship is equal to that of the water

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How many of the following materials can be attracted by a magnet?

1. Plastic

2. Carbon

3. Aluminium

4. Stainless Steel

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Two identical spring balances S₁ and S₂ are connected one after the other and are held vertically as shown in the figure. A mass of 10 kg is hanging from S₂. If the readings on S₁ and S₂ are W₁ and W₂ respectively, then :

Two identical containers X and Y are connected at the bottom by a thin tube of negligible volume. The tube has a valve in it, as shown in the figure. Initially container X has a liquid filled up to height h in it and container Y is empty. When the valve is opened, both containers have equal amount of liquid in equilibrium. If the initial (before the valve is opened) potential energy of the liquid is P₁ and the final potential energy is P₂ then :

A rectangle ABCD is kept in front of a concave mirror of focal length f with its corners A and B being, respectively, at distances 2f and 3f from the mirror with AB along the principal axis as shown in the figure. It forms an image A'B'C'D' in front of the mirror. What is the ratio of B'C' to A'D'?

Shown in the figure are two plane mirrors XY and YZ (XY ⊥ YZ) joined at their edge. Also shown is a light ray falling on one of the mirrors and reflected back parallel to its original path as a result of this arrangement. The two mirrors are now rotated by an angle θ to their new position X'YZ', as shown. As a result the new reflected ray is at an angle α from the original reflected ray. Then :

What is the total resistance in the following circuit element?

Inhabitants are unaware of the speed of rotation of the planet Earth because

1. the angular velocity is constant for each place on the Earth's surface

2. the atmosphere rotates with the Earth

3. there are no nearby objects, either stationary or moving at a rate different from that of the Earth

Which of the following statements correctly explains/explain the existence of a positive force between two electric charges?

1. Both the charges are positive.

2. Both the charges are negative.

3. Both the charges are oppositely charged.

Why are the tyres of aircrafts made of conducting rubber?

1. So that the charge accumulated on the aircraft in flight, by rubbing the air, can easily be transferred to ground on landing.

2. So that the charge accumulated due to the operation of various electronic equipments in the aircraft in flight can easily be transferred to ground on landing.

The electrostatic potential doesn't depend on which of the following 

(1) It depends on the charge

(2) It depends on the endpoints of the path through work done

(3) It depends on the path taken for the work done 

(4) It depends on the amount of work done 

Consider the following statements about Light year:

1. Light year is a unit for measurement of very large distances.

2. Light year is a unit for measurement of very large time intervals.

3. Light year is a unit for measurement of intensity of light.

Which of the statements given above is/are correct?

Which of the following pairs of physical phenomenon and the discover is/are correctly matched?