Smart learn2

  Speed Speed is the distance (D) travelled divided by the time (Δt) taken for the journey. Quantity: speed (v)  Unit: metre per second  Unit symbol: m⋅s−1 Velocity Velocity is the change in position of a body divided by the time it took for the displacement to occur. Quantity: average velocity (→v)  Unit name: metre per second  Unit symbol: m⋅s−¹ "Distance and time are scalars and therefore speed will also be a scalar." Example:  James walks 2km away from home in 30 minutes. He then turns around and walks back home along the same path, also in 30 minutes. Calculate James’ average speed and average velocity. Step 1: Identify what information is given and what is asked for The question explicitly gives the distance and time out (2km in 30minutes) the distance and time back (2 km in 30 minutes) Step 2: Check that all units are SI units. The information is not in SI units and must therefore be converted. To convert   👉Convert (km) to (m),  we know t...

  Introduction to Motion in One Dimension This tutorial is about how things move along a straight line or, more scientifically, how things move in one dimension. This is useful for learning how to describe the movement (motion) of cars along a straight road or of trains along straight railway tracks. There are three features of motion that we use to describe exactly how an object moves. They are: Did You Know? The jerk is the name we give to how fast the acceleration is changing. Position   tells us about an object’s location or displacement   tells us about change of location Speed   tells us how fast the object is moving & velocity   tells us how fast the object is moving and where it is moving to. Acceleration   tells us exactly how fast the object’s speed and velocity are changing. Definition: Distance Distance is the total length of the path taken in going from the initial position, to the final position.  Distance is a scalar quantity. Quanti...

  Introduction to Vectors and Scalars We come into contact with many physical quantities in the natural world on a daily basis. For example, things like time, mass, weight, force, and electric charge, are physical quantities with which we are all familiar. We know that time passes and physical objects have mass. Things have weight due to gravity. We exert forces when we open doors, walk along the street and kick balls. We experience electric charge directly through static shocks in winter and through using anything which runs on electricity. There are many physical quantities in nature, and we can divide them up into two broad groups called vectors and scalars. Scalars and Vectors Scalars are physical quantities which have only a number value or a size (magnitude). A scalar tells you how much of something there is. Definition: Scalar A scalar is a physical quantity that has only a magnitude (size). For example, a person buys a tub of margarine which is labelled with a mass of 500g....

Questions 1. When a p-n junction is under reverse bias mode, the width of the depletion region will be increased. Which of the following statements is true? A. The applied voltage moves the electrons from n-type region to p-type region. B. The applied voltage moves the holes from p-type region to n-type region. C. The applied voltage drives the electrons towards n-type region. D. The applied voltage drives the holes towards n-type region. Explanation: Under reverse bias mode, the electrons in the n-region are pulled away from the depletion region, leaving more immobile positive ions in the region. In other words, the electrons are driven towards the n-region. Answer is C 2. Which statement about conduction of electricity in semiconductors is correct? A. The presence of impurities in a semiconductor is used to decrease its resistance. B. In a semiconductor, there is a large energy gap between the conduction and valence bands. C. At low temperatures, free electrons are found both in the ...