CTET Practice Test: Science-1 - CTET & State TET MCQ

When pressure is increased, the melting point of ice decreases.

• In general, increasing pressure lowers the melting point of ice.
• This phenomenon is due to the unique properties of water.
• Under high pressure, ice transforms to liquid at a lower temperature.
• This is why ice skates glide on ice; the pressure from the skate blade melts the ice.

Sprayer functions are based on Bernoulli’s principle.

This principle explains how the speed of a fluid affects its pressure. Here are some key points:

• As the speed of the fluid increases, its pressure decreases.
• This principle is crucial for understanding how sprayers work.
• It helps in achieving an even distribution of the liquid being sprayed.

Therefore, the correct answer is A.

The fabrication of a transistor involves creating a crucial component for electrical and electronic circuits. Transistors are primarily made from:

• Silicon - the most common material used due to its excellent semiconductor properties.
• Germanium - another option, though less frequently used in modern applications.
• Other semiconductor materials can also be employed depending on specific requirements.

Overall, the choice of material is vital for ensuring optimal performance in various electronic devices.

​An electric current in a metal wire results from the flow of electric charge, primarily carried by moving electrons. These electrons move through the wire, creating a current that can power devices and circuits.

The nature of fuse wire is low melting point.

An electric fuse is a protective device that:

• Safeguards electrical equipment in a circuit.
• Breaks the circuit during a short circuit.
• Has a low melting point, allowing it to melt quickly under excess current.

This quick melting action helps prevent damage to delicate components and reduces the risk of fires.

A transformer is a device that adjusts the voltage in an AC electrical circuit.

• It can increase (step-up) or decrease (step-down) voltage levels.
• This is essential for efficient power distribution.
• Transformers do not convert DC to AC or vice versa.
• They also do not change electrical energy into mechanical energy.

In summary, a transformer plays a crucial role in managing AC voltage levels.

Ozone layer thickness is measured in Dobson units. These units indicate the physical thickness of the ozone layer if it were compressed to sea level conditions. Key points include:

• 1 Dobson unit corresponds to a thickness of 0.01 mm at Standard Temperature and Pressure (STP).
• Dobson units provide a clear measurement of the ozone layer's density and concentration.
• Understanding these units is essential for studying ozone depletion and atmospheric science.

Lactometer is used to measure the density of milk.

The butyrometer measures the fat content in milk and dairy products.

• A lactometer works by floating in the liquid; the level at which it floats indicates the density.
• This instrument is essential for ensuring the quality and composition of milk.
• In contrast, a thermometer simply measures temperature and does not provide density information.

It is difficult to walk on the ice compared to the road because ice has lower friction than the road. This means:

• The smooth surface of ice provides less grip.
• On the road, the rough texture increases friction, helping you to push off effectively.
• As a result, walking on the road is easier and safer.

Statics is a branch of mechanics that deals with objects in a state of rest.

It focuses on:

• The study of forces acting on stationary objects.
• Understanding how these forces maintain equilibrium.
• Applications in engineering and architecture.

In summary, statics is concerned with the situation of rest, ensuring that systems remain balanced and stable without movement.

The colour of the stars indicates their temperature. Here’s how it works:

• If a star appears blue, it is very hot and generally younger.
• A red star is cooler and typically older.
• The temperature of a star affects its colour, with hotter stars emitting blue light and cooler stars emitting red light.

Thus, the colour of a star is a key factor in determining its temperature.

Sunglasses typically have a power of 0 Diopter because they are designed to protect the eyes from sunlight without correcting vision.

• Diopter is a unit of measurement for the optical power of lenses.
• Sunglasses do not alter vision; they mainly block harmful UV rays.

​A pendulum clock runs faster in winter because in winter the length of the pendulum or the swing become smaller due to contraction and the clock begin to run fast.

Oil spreads on water surface because the surface tension of oil is less than that of water.

• This difference in surface tension allows oil to spread out.
• When two liquids meet, the one with lower surface tension will spread more easily.
• As a result, oil forms a thin layer on the water's surface.

A sudden fall in the barometer reading often signals that the weather is changing. Here's how it typically affects the forecast:

• A rapid decrease usually indicates stormy weather is imminent.
• This is because low pressure is often associated with storms and unsettled weather conditions.
• Such changes can also suggest an incoming weather front.

Hence, a sudden drop in barometric pressure is a good predictor of stormy conditions.

Due to the refraction of light, the sun can be seen a few minutes before sunrise and a few minutes after sunset. This phenomenon occurs because:

• The Earth's atmosphere bends light rays.
• This bending allows us to see the sun's light even when it is just below the horizon.
• As the sun rises, its light is refracted, making it visible earlier.

This effect is an example of how atmospheric conditions influence our perception of celestial bodies.

The convex mirror creates an upright image of objects and provides a wider field of view than a plane mirror. This type of mirror is commonly used in car rear-view mirrors for enhanced visibility.

The eye lens is made of a fibrous, jelly-like material. The ciliary muscles can change its curvature, which in turn alters its focal length. Here’s how it works:

• When the ciliary muscles are relaxed, the lens becomes thin, increasing its focal length. This allows us to see distant objects clearly.
• When focusing on nearby objects, the ciliary muscles contract, making the lens thicker. This reduces its focal length, enabling clear vision of close items.

Microwaves are high-frequency signals that range from 300 MHz to 300 GHz. These signals can transmit thousands of channels simultaneously, making them an extremely versatile communication medium.

Key points about microwaves in telecommunications:

• Microwaves are commonly used for point-to-point communications.
• They are employed by the telecommunications industry for both terrestrial relays and satellite communication.

A dynamo, also referred to as an electrical generator, produces direct current via a commutator. Its primary function is to:

• Convert mechanical rotation into electric current.
• Operate based on Faraday's law of electromagnetic induction.

In essence, a dynamo transforms energy from one form to another, making it a vital component in electricity generation.