Free Practice Questions for Physics in General-studies

Out of the above option, Rectilinear motion - A stone is thrown in air at an angle upwards, the statement is wrong.

Important Points:

• The motion of an object is in a straight line and the magnitude of displacement in the same direction is equal to the total length of the path. It is called Rectilinear motion. 
• It is also called translational motion.

Examples : a man/car moving in a straight line, a ball falling from a height, a train running on a straight track, etc.

Option Explanation:

• Oscillating motion : When a body moves to and fro about a fixed point on a fixed path, performing harmonic motion, called oscillatin motion. 

Example: pendulum of a clock, child swinging on a swing. 

• Rotational Motion: When every particle of an object moves in a circular path around the axis, it is called rotational motion.

Example: wind mill, fan. 

• Periodic Motion:  The motion in which an object or body repeats its own motion in a fixed interval of time and on a fixed path is called periodic motion.

A decrease in humidity factors increases the rate of evaporation. 

Important Points:

• Liquids change into vapour through the process of evaporation. 
• Factors affecting the rate of evaporation of liquids are temperature, surface area, wind speed, and humidity.
• Temperature-  The rate of evaporation increases as the temperature increases. The rate of evaporation and the temperature are directly proportional to each other.
• Surface area- The rate of evaporation increases with increase in surface area. The rate of evaporation and the Surface area are directly proportional to each other.
• Wind speed-  The rate of evaporation increases with the movement of the wind.The rate of evaporation and wind speed are directly proportional to each other.
• Humidity- The amount of water vapour present in the air is known as humidity. The rate of evaporation and humidity are inversely proportional to each other.

Acceleration is equal to the rate of change of velocity. 

Important Points:

Acceleration is  also a vector quantity. The S.I.unit of acceleration is the metre per second square (m/s²).

a=(v-u)/t  

where,

a= acceleration, v= final velocity, u= initial velocity, t= time

• The slope of the acceleration-time graph is △a/△t.
• The area under the acceleration-time graph represents the change in velocity.

Phenol is used in making of plastics. Bakelite is formed by using phenol as a monomer.

Important Points:

• Heat and electricity do not conduct well through bakelite.
• Electrical switches, utensil handles, and other items are made with it.
  Because it is a thermosetting plastic, it cannot be moulded again or used again.
• Monomers of Bakelite are phenol and formaldehyde.

Options Explanation:

Venus does not have any moon or satellite of its own.

Important Points:

• Venus is the second planet from the Sun and the closest planet from the Earth.
  
• It is also called the Earth's twin because it is similar to the Earth in size and density.
• It is also called the morning or evening star.
• Venus does not have any moon or satellite of its own.
• Venus rotates on its axis from east to west while Earth rotates from west to east.

Loudness refers to how loud or soft a sound seems to a listener. Loudness of sound is directly proportional to the square of the amplitude of vibration. The more the amplitude of vibration, the sound is the loud. The lesser the amplitude of vibration, the sound is feeble. Loudness does not change with change in frequency. 1 decibel is equal to one-tenth of a bel. If a given sound is perceived to be as loud as a 60 dB sound at 1000 Hz, then it is said to have a loudness of 60 phons. 

1 phon =1 decibel at 1000Hz 

IMPORTANT FACTS

Pitch:-

• It represents shrillness or flatness of sound. 
• Frequency determines the pitch of the sound.
• Higher the frequency of sound wave, the higher will be the pitch of sound. Lower the frequency, lower the shrill or pitch. 
• The SI unit of Frequency is Cycle per second or Hertz (Hz).
• Example - Babies voice has more frequency and thereby more shrill than an adult voice.

Gamma rays are the most energetic waves.

Important Points:

• Gamma rays are highly penetrating and cause serious damage when absorbed by living tissue.
• Thick sheets of lead are used to protect objects from the harmful effects of gamma rays.
• These waves have a small ionizing power. Gamma rays are used to detect metal defects in metal castings.

The period of oscillation of a simple pendulum of constant length at earth surface is T. When a pendulum clock is taken upto a hill, its time period will be greater than T. This is due to decrease in the value of g. 

Important points

• The time period of oscillation of the pendulum clock is increased on the moon’s surface.
• This is because on the moon surface, the value of g is 1/6 times the value of g on earth. That is pendulum clock is slowed down.
• If the lift is going up with accelerated motion, then the time period of the pendulum is decreased because the acceleration due to gravity is increased. 
• While the lift is coming down, then the periodic time of the pendulum is increased because the effective value of g is decreased from its actual value.

The SI unit of electric potential difference is volt (V), named after Alessandro Volta.

Important Points:

• The electric potential difference between two places in a current-carrying electric circuit represents the work done to convey a unit charge from one point to the other. 
• Work done (W)/Charge (Q) equals Potential difference (V) between two locations. 
• The volt (V), named after Alessandro Volta, is the SI unit of electric potential difference. 
• 1 V = 1 J/C
• The potential difference is measured using a device known as a voltmeter. 
• The voltmeter is always connected in parallel across the locations to be measured for potential difference.

The motion of a simple pendulum shows both periodic and oscillatory motion.

Important point :

• The motion of a simple pendulum shows both periodic and oscillatory motion. A simple pendulum consists of a mass (known as a bob) suspended by a light, inextensible string, which is attached to a fixed point.
• When the bob is displaced from its equilibrium position and released, it oscillates back and forth, repeating the motion periodically.
• The motion of a simple pendulum is periodic because it repeats after a fixed time interval, which is called the time period of the pendulum.

Option Explanation:

• The motion of a horse pulling a cart on a straight road, the motion of a child in a carousel, and the motion of a train on a straight bridge do not exhibit both periodic and oscillatory motion. While they may exhibit some periodicity, they do not oscillate about the equilibrium position.

Units of length:

• 1 fermi = 1 f = 10^–15 m 
• 1 astronomical unit = 1 AU (average distance of the Sun from the Earth) = 1.496 × 10¹¹ m 
• 1 light year = 1 ly= 9.46 × 10¹⁵ m (distance that light travels with velocity of 3 × 10⁸ m s^–1 in 1 year) 

Units of time:

• Lunar month (It is the time between two successive new moons or full moons) and Leap year (It is a calendar year that contains an additional day) are the units of time. 
• 1 h = 60 min 
• 1 d = 24 h = 1440 min
• 1y = 365.24 d 

IMPORTANT FACTS

Fundamental SI units-

• Length – metre(m)
• Current – Ampere(A)
• Amount of substance – Mole
• Mass – Kilogram(Kg)
• Time – Seconds(s)
• Luminous intensity – Candela(cd)
• Temperature – Kelvin(K)

Seismic waves are recorded by an instrument called the seismograph.

Important Points:

• Seismic waves are of two types: body waves and surface waves.
• The first seismograph was developed in 1890. 

The speed of sound decreases when we go from solid to gaseous state and if temperature decreases.

Important Points:

• The speed of sound in a medium depends on temperature of the medium.  
• In any medium as we decreases the temperature the speed of sound decreases. 
• For example, the speed of sound in air is 331 m s^–1 at 0 ºC and 344 m s^–1 at 22 ºC. 
• Speed of sound is more on humid day than on dry day.

When an object follows a circular path at a constant speed, the motion of the object is called uniform circular motion. 

Important Points:

• The object experiences acceleration because its velocity changes direction continuously.
• The acceleration is always in the direction of the circle's centre.
  The velocity vector is always perpendicular to the acceleration vector.

Velocity of Uniform Circular Motion :

• Velocity =  Circumference of circle / Time
• v = 2πr/ t

where,

• v - velocity of the object
• r - radius of the circular path
• t - time taken by the object

Frequency of a sound wave (f)= 2Hz

Wavelength of a sound wave (λ) = 100 cm = 1m

Velocity of a sound wave (v) = f λ = 2 x 1 = 2m/s

Time taken by the sound wave to travel 1 km distance = distance/velocity = 1/2 =0.5s

Since the train is moving with constant speed that is equal distance in equal interval of time, the shape of the distance-time graph is straight line.

Important points

• The slope of position – time graph represents velocity.
• The slope of velocity –time graph gives acceleration.
• The area under the velocity-time graph gives displacement. 

OPTIONS EXPLANATION

• If the distance time graph of the motion of an object is a straight line and parallel to the time axis, then it may be concluded that the object is not moving, Object is at rest.

• If the distance time graph of the motion of an object is a not a straight line, then it may be concluded that the object is moving with an accelerated motion.

• The slope of the distance- time graph is equal to the speed of the object.

The work done in pulling the mass M is positive.

Important points

Work-

• Work is defined as the product of the force applied on an object and displacement caused due to the applied force in the direction of the force. 
• The unit of Work is Newton meter (Nm) or joule (J).
• If the force and the displacement are inclined at an angle, then the work done is given as W = Fscosθ
• When both the force and the displacement are in the same direction, then there is positive work.
• When the force and the displacement are in the opposite direction, negative work is done.
• If force and displacement are acting perpendicular to each other then the work done is zero.

Laboratory thermometer is used to measure the temperature of common objects.The range of a laboratory thermometer is generally from –10°C to 110°C.

Important points:

• Temperature is measured by a device called a thermometer. 
• The thermometer that measures our body temperature is called a clinical thermometer.
• The temperature of the human body normally does not go below 35^oC or above 42^oC.
• That is the reason that this thermometer has the range 35^oC to 42^oC. 
• The normal temperature of human body is 37°C. 
• The SI unit of temperature is Kelvin, and degree Celsius is the commonly used unit of temperature.

Vacuum is a non-dispersive medium in which all colors travel with the same speed, so sunlight reached us in the form of white light and not as its components.

Important Points:

• When a narrow beam of sunlight, usually called white light, is incident on a glass prism, the emergent light is seen to be consisting of several colors (Violet, Indigo, Blue, Green, Yellow, Orange and Red).
• The red light bends minimum, while the violet light bends the most.
• The rainbow is an example of the dispersion of the sunlight by the water drops in the atmosphere.