intro
Question 1:
What is the constant nature of Gravitational Potential Energy?
Topic: Energy in Physics
Correct Answer: A) Always Negative
- The characteristic property of Gravitational Potential Energy is that it maintains a consistent negative value.
- This is due to the fact that the energy is determined by the position of an object within a gravitational field, and its value decreases as the object moves away from the source of the gravitational field.
- Therefore, the correct option is A, "Always Negative".
Question 2:
What is the impact on work done when the magnitude of applied force is amplified?
Topic: Work and Energy in Physics
Correct Answer: A) Increased
- The formula for work is given by Work = Force x Distance (W = F x d). Hence, if the magnitude of force (F) increases, the work done also elevates proportionally.
- Therefore, the correct response is A, "Increased".
Question 3:
If a force of 10N is exerted on an object for a duration of 3 seconds, resulting in a displacement of 6 meters, what would be the power delivered by the source?
Topic: Work, Energy and Power in Physics
Correct Answer: D) 20 Watts
- In physics, power (P) is calculated by multiplying force (F) by velocity (V).
- Here, velocity can be obtained by dividing the displacement (S) by the time (t).
- So, P = FV = F x (S/t) = 10N x (6m/3s) = 20 Watts.
- Hence, the correct answer is D), "20 Watts".
Question 5:
What will be the man's weight in the free-falling elevator?
Topic: Free Fall in Physics
Correct Answer: D) Zero
- When an elevator free-falls, the forces acting upon the body are cancelled out leading to a state of "apparent weightlessness".
- This condition arises because all supporting forces are eliminated and the person or object effectively becomes a falling object.
- Therefore, the man's weight in a free-falling elevator would be zero (option D).
Question 6:
If the gravitational field performs negative work, what happens to the potential energy (P.E) of the body?
Topic: Energy and Work in Physics
Correct Answer: B) Necessarily increases
- When the gravitational field does negative work, height ('h') increases.
- An increase in height results in an increase in gravitational potential energy (P.E = mgh, where m is mass, g is gravitational acceleration, and h is height).
- Therefore, the potential energy of the body necessarily increases (option B).
Question 7:
Initially at rest, a block of 5 kg is displaced in the x-direction by 4 meters. It experiences a force of 20 Newtons. If the block gains kinetic energy of 40 Joules, what is the angle that the force makes with the x-axis?
Topic: Force and Motion in Physics
Correct Answer: D) 60°
- The work done by a force (W) is given by the equation W = F x d x cos(θ), where F is the force, d the distance and θ (theta) is the angle between the direction of force and the direction of displacement.
- Substituting the given values: 40 = 20 x 4 x cos(θ), gives us cos(θ) = 1/2 which implies θ = 60°.
- Therefore, the correct answer is D) "60°".
Question 8:
Among the following options, which one is the largest energy unit?
Topic: Energy Measurement in Physics
Correct Answer: B) KiloWatt-hour
- The basic energy unit in the International System of Units (SI) is the Joule. However, other units of measure can also express energy.
- 1 Joule equals 1 kg m^2/s^2. A Kilowatt-hour (kWh) equals 1000 W for 3600 seconds, which when converted to Joules is 3,600,000 Joules.
- An erg is a CGS unit of energy, where 1 erg equals 10^-7 Joules. An Electron Volt (ev) is the energy change for an electron moving across an electric potential difference of one volt, equivalent to approximately 1.6x10^-19 Joules.
- Comparatively, a Kilowatt-hour (option B) is the largest energy unit and is primarily used in electrical energy consumption measurements.
Question 9:
A horse and a dog are running at an identical velocity. If the horse's mass is tenfold that of the dog, what will be the kinetic energy ratio of the two?
Topic: Kinetic Energy in Physics
Correct Answer: D) 10:1
- Given that the horse (m2) and the dog (m1) have the same speed (V), and the horse's mass is ten times that of the dog (m2 = 10m1), we can deduce the kinetic energy ratio.
- The kinetic energy (K.E) is given by the formula K.E = ½mv2. Thus, the ratio of the kinetic energies equals 10:1.
- Therefore, the correct option is D) "10:1".
Question 10:
How many times do the tides typically elevate sea water in a day?
Topic: Tides in Earth Science
Correct Answer: B) Twice
- The Moon and Sun's gravitational force and the Earth's rotation cause tides to rise and fall.
- As the Earth rotates, each point passes through both bulges each day. Therefore, most places see two high tides and two low tides each day (four tides in total). However, considering the significant rise in water as a tide, it occurs twice a day.
- So, the correct answer is B) "Twice".
Question 11:
Two objects, one light and one heavy, possess the same kinetic energy. Which one will have a larger momentum?
Topic: Momenta in Physics
Correct Answer: B) The heavy object
- A momentum's formula is `P = mv`, where `P` is momentum, `m` is mass, and `v` is velocity.
- Therefore, a heavier object would have a higher momentum, given the kinetic energy being equal for both.
- Therefore, the correct answer is B) "The heavy object".
Question 12:
Which planet in our solar system possesses the greatest escape velocity?
Topic: Escape Velocity in Astronomy
Correct Answer: C) Jupiter
- Escape velocity refers to the minimum speed an object must have to break free from a planet's gravitational field.
- Jupiter, having the most substantial mass among the planets in our solar system, subsequently has the highest escape velocity at 59.5 km/s.
- Therefore, the correct answer is C) "Jupiter".
Question 13:
What is the equivalent of 25,000 watts in horsepower?
Topic: Power Conversion in Physics
Correct Answer: D) 33.5 hp
- The conversion between watts and horsepower is given by the equivalence 1 hp = 746 watts.
- Therefore, to convert 25,000 watts into horsepower, we divide by 746, which gives approximately 33.5 hp.
- Therefore, the correct answer is D) "33.5 hp".
Question 14:
What does the unit J/S represent in physics?
Topic: Units in Physics
Correct Answer: B) Power
- In physics, the unit J/S stands for Joules per second, which is the standard unit of measure for power.
- Power, in physics, is defined as the rate at which work is done or the amount of energy transferred or converted per unit time.
- Thus, the correct answer is B) "Power".
Question 15:
What will be the ball's kinetic energy at one-third of its initial height when it is thrown upwards at a velocity of v?
Topic: Energy in Physics
Correct Answer: D) v2/6g
- The equation relating the gain in potential energy (P.E) and loss in kinetic energy (K.E) is mgh = 1/3 (1/2mv2), where mg denotes mass, g is gravity's acceleration, and h represents height.
- By rearranging this equation, we can find h = v2/6g.
- Hence, the correct answer is D) "v2/6g".
Question 16:
What type of energy source is geothermal energy?
Topic: Energy Sources in Environmental Science
Correct Answer: C) Renewable
- Geothermal energy refers to the heat derived from the Earth's interior.
- As this heat is continuously produced inside the Earth, geothermal energy is considered a renewable source of energy.
- In addition to heating buildings and producing electricity, geothermal energy can also be used for bathing.
- So, the correct answer is C) "Renewable".
Question 17:
A block weighing 2kg is pushed up a slope that is 10m high. If the total work done equals 300J (considering g = 10m/s2), what is the amount of work done against friction?
Topic: Work and Energy in Physics
Correct Answer: A) 100 J
- The potential energy stored due to the block's position can be calculated using the formula mgh = 2 × 10 × 10 = 200J.
- The total work done is given as 300J.
- The work done against friction can be deduced by subtracting the stored potential energy from the total work done; that is, 300J - 200J = 100J.
- Hence, the correct answer is A) "100 J".
Question 18:
Two girls have weights in the ratio 4:5. They climb a staircase taking time in the ratio 5:4. What is the ratio of their power?
Topic: Power in Physics
Correct Answer: C) 16/25
- The power exerted by each girl is inversely proportional to the time taken and directly proportional to the weight.
- Given the weight ratio of 4:5 and time ratio of 5:4, these ratios can be combined to calculate the power ratio.
- Multiplying the weight ratio by the inverse of the time ratio gives the power ratio, which is (4/5) * (4/5) = 16/25.
Question 19:
What is the relationship between escape velocity (Vesc) and orbital speed (Vo)?
Topic: Escape Velocity in Astronomy
Correct Answer: C) Vesc = √2 Vo
- Escape velocity (Ve) and orbital speed (Vo) are related such that Ve = √2Vo.
- This can be deduced from the formula Vo = Ve/√2, by rearranging to solve for Ve.
- Therefore, the correct answer is C) "Vesc = √2 Vo".
Question 20:
According to the principle of work, how much work is performed when a student sits still and studies the entire night?
Topic: Work in Physics
Correct Answer: B) No work at all
- The formula for work is Work = Force x Displacement.
- Given that the student is sitting still, there is no displacement.
- Therefore, regardless of the time or effort spent studying, no work is done in the physics sense.
- Hence, the correct answer is B) "No work at all".
Question 21:
A person exerts force on a wall, but it remains unmoved. What is the work done in this instance?
Topic: Work in Physics
Correct Answer: C) No work is performed
- The work done is calculated as the product of the force applied and the displacement in the direction of the applied force, represented as Work (W) = Force x Displacement.
- In this situation, despite the application of force, there is no displacement as the wall remains unmoved. Thus, Displacement = 0.
- This implies that the work done equals zero since the displacement is zero.
- Therefore, the correct answer is C) "No work is performed".
Question 22:
At what angle is the work considered to be at a maximum positive value?
Topic: Work in Physics
Correct Answer: A) 0°
- The work done, represented as W, is calculated as the product of force and displacement multiplied by the cosine of the angle between them (W = Force x Displacement x cosθ).
- When the angle θ is 0°, the cosine of the angle is +1, which results in the work being at its maximum positive value (W = +Force x Displacement).
- Therefore, the correct answer is A) "0°".
Question 23:
Suppose the kinetic energy of an object is amplified by 300%. By what percentage will its momentum be affected?
Topic: Energy and Momentum in Physics
Correct Answer: A) 100%
- KE is proportional to the square of momentum (P) in classical physics, following the equation KE = P2/2m.
- Therefore, if the kinetic energy is increased by 300%, the momentum will increase by the square root of 300%, which is approximately 100%.
- Hence, the correct answer is A) "100%".
Question 24:
Which type of force is incapable of doing work on the object it influences?
Topic: Forces in Physics
Correct Answer: C) Centripetal force
- Force and displacement are defined as the dot product of work. It is only done if the force has a component along the direction of displacement.
- Due to the fact that centripetal forces always act perpendicular to the direction of motion, they don't have any components along the motion direction.
- Therefore, no work is done by centripetal force.
- Hence, the correct answer is C) "Centripetal force".
Question 25:
What is the angle at which the vector components are equal?
Topic: Vectors in Physics
Correct Answer: B) 45°
- The components of a vector are equal when it is split into two directions at an angle of 45°.
- This is because the cosine and sine of 45° are equal, meaning the horizontal and vertical components of the vector will also be equal.
- Hence, the correct answer is B) "45°".
Question 26:
A chunk with a mass of 100g glides across a coarse flat surface. The velocity of the chunk decreases from 10m/s to 5m/s. Determine the heat energy produced during this process.
Topic: Energy Transformation in Physics
Correct Answer: A) 3.75 J
- The process of a block slowing down on a rough surface involves conversion of kinetic energy into thermal energy due to friction.
- Kinetic energy can be transformed using the equation KE = 1/2 m v2, where m = mass, v = velocity.
- The thermal energy developed is equivalent to the loss in kinetic energy. Using the formula, Thermal Energy = 0.5 * m * (v12 – v22), where v1 is the initial velocity and v2 is the final velocity.
- Substituting the given values (m = 0.1 kg, v1 = 10 m/s, v2 = 5 m/s) into the formula, we get Thermal Energy = 0.5 * 0.1 * (102 – 52) = 3.75 J.