Physics 11th–12th Standard Challenge

Question 1

In projectile motion near Earth's surface with air resistance neglected, which quantity remains constant throughout the flight?

Accepted Answer

Horizontal component of velocity

Answer

Vertical component of velocity

Answer

Magnitude of acceleration

Answer

Kinetic energy

Question 2

A body moves in a circle of radius r with speed v. If the speed is doubled while the radius stays the same, the centripetal acceleration becomes:

Accepted Answer

Four times the original value

Answer

Twice the original value

Answer

Half the original value

Answer

Unchanged

Question 3

Why does a satellite in a stable circular orbit around Earth appear weightless to astronauts inside it?

Accepted Answer

Because both satellite and astronauts are in continuous free fall

Answer

Because gravity is absent in orbit

Answer

Because the satellite is beyond Earth's atmosphere

Answer

Because the mass of astronauts becomes zero in space

Question 4

For an ideal gas undergoing an isothermal expansion, which quantity remains constant?

Accepted Answer

Temperature

Answer

Pressure

Answer

Volume

Answer

Internal energy always decreases

Question 5

Two resistors of 6 Ω and 3 Ω are connected in parallel. What is their equivalent resistance?

Accepted Answer

2 Ω

Answer

9 Ω

Answer

1.5 Ω

Answer

3 Ω

Question 6

A potentiometer is preferred over a voltmeter for comparing EMFs because it:

Accepted Answer

Measures potential difference without drawing current from the cell

Answer

Has lower resistance and draws more current

Answer

Works only with alternating current

Answer

Directly measures internal resistance in one reading

Question 7

In Young's double-slit experiment, if the wavelength of light is increased while slit separation and screen distance stay the same, the fringe width will:

Accepted Answer

Increase

Answer

Decrease

Answer

Remain unchanged

Answer

First increase then decrease

Question 8

When light travels from air into glass, which statement is correct?

Accepted Answer

Its speed decreases while frequency remains the same

Answer

Its speed and frequency both increase

Answer

Its wavelength remains unchanged

Answer

Its frequency decreases while speed stays the same

Question 9

The magnetic field at the center of a circular current-carrying loop depends directly on:

Accepted Answer

Current through the loop

Answer

Radius of the loop only

Answer

Square of the resistance

Answer

Time period of rotation

Question 10

In an AC circuit containing only a pure inductor, the current:

Accepted Answer

Lags the voltage by 90°

Answer

Leads the voltage by 90°

Answer

Is in phase with the voltage

Answer

Has zero phase difference only at resonance

Question 11

Which nuclear phenomenon is the basis of energy production in the Sun?

Accepted Answer

Nuclear fusion of light nuclei

Answer

Nuclear fission of uranium

Answer

Radioactive decay of heavy elements

Answer

Electron-positron annihilation in bulk matter

Question 12

Einstein received the Nobel Prize primarily for explaining:

Accepted Answer

The photoelectric effect

Answer

Special relativity

Answer

General relativity

Answer

Brownian motion

Question 13

If the de Broglie wavelength of a particle is to increase, which change would achieve that most directly?

Accepted Answer

Reducing its momentum

Answer

Increasing its momentum

Answer

Increasing its charge

Answer

Reducing its potential energy only

Question 14

In a semiconductor diode under forward bias, the depletion region generally:

Accepted Answer

Narrows, allowing easier charge flow

Answer

Widens and blocks current more strongly

Answer

Disappears completely at any voltage

Answer

Reverses its polarity but keeps the same width

Question 15

A transformer used for long-distance power transmission is designed mainly to:

Accepted Answer

Raise voltage so current is lower for the same power

Answer

Increase current and reduce voltage to minimize loss

Answer

Convert AC directly into DC at the source

Answer

Store electrical energy in magnetic form permanently

Physics 11th–12th Standard Challenge

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