Ohm’s law holds for peak, effective, and instantaneous values of voltage and current in AC circuits.
The phase angle between voltage and current in an AC circuit with only resistance is zero.
V^2 = VR^2 + (VL – VC)^2 in an LCR series circuit.
The average power dissipated per cycle in a resistor with a voltage V = V0cosωt is V0^2/√2R.
When two identical coaxial circular loops carry equal currents in the same direction, the current in each decreases.
An inductor may store energy in its magnetic field.
Vector addition obeys commutative, distributive, and associative laws.
The direction of a vector in space is specified by three angles.
A vector can be multiplied by a number, which may be dimensionless, dimensional scalar, or negative.
The unit vector n^ is along a normal on a surface.
The rectangular coordinate system is also called the Cartesian coordinate system.
The maximum number of rectangular components a vector can have is 3.
Cosθi^ + Sinθj^ is a unit vector in the direction at angle θ with the x-axis.
A vector A = 2i^ + 2j^ + 3k^ has direction at 45° with the x-axis and magnitude 2.
An angle between two vectors A and B can be determined by their dot product.
Two forces of equal magnitudes in opposite directions and making an angle of 120° with each other are in equilibrium.
Three coplanar forces keeping a body in equilibrium are concurrent.
Torque is the turning effect of force.
It is easier to turn a steering wheel with both hands because the couple acts on the wheel.
The cross product of i^ x j^ is equal to 1.
The unit vector in the direction of vector A = 2i^ – 2j^ + k^ is (2i^ – 2j^ + k^)/3.
The cross product of two vectors is a negative vector when they are rotated through 270°.
Both tanθ and tan(180° + θ) have positive values in the first and third quadrants.
The magnitude of i^. (j^ x k^) is 1.
A = Ax i^ + Ay j^ + Az k^, B = Bx i^ + By j^ + Bz k^, then A. B = Ax Bx + Ay By + Az Bz.
A body in equilibrium may be at rest or in uniform motion.
The maximum value of the static frictional force is μsN.
Friction opposes the relative motion between any two objects.
The weight of a body acts through its center of gravity.
The acceleration due to gravity decreases with increasing altitude above the Earth’s surface.
An object in motion has a tendency to remain in motion at the same speed in the absence of an external force.
The mass of an object remains constant regardless of its location.
The force of gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance.
The acceleration due to gravity is the same at all points on the Earth’s surface.
Inertia is the property of an object to resist changes in its state of motion.
The momentum of an isolated system is conserved.
The SI unit of momentum is kg.m/s.
Work done by a force is scalar and has no direction.
The unit of energy and work is joule.
Energy can be transformed from one form to another, but it cannot be created or destroyed.
Power is the rate of doing work or transferring energy.
The momentum of an object is the product of its mass and velocity.
The weight of an object is the force with which it is attracted towards the Earth.
A change in momentum produces a force on an object.
A body at rest will remain at rest unless acted upon by an external force.
The acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass.
The quantity 1 kg m/s^2 is equivalent to 1 newton.
An object will float in a liquid if its average density is less than the density of the liquid.
The temperature remains constant during a change of state of matter.
The average kinetic energy of molecules increases with an increase in temperature.
The absolute temperature scale is the Kelvin scale.
Heat energy is transferred from a region of higher temperature to a region of lower temperature.
The heat required to raise the temperature of 1 gram of water by 1 degree Celsius is called a calorie.
The process of a gas changing directly from a solid to a gas is called sublimation.
The specific heat capacity of a substance is the amount of heat required to raise the temperature of 1 gram of the substance by 1 degree Celsius.
The Kelvin scale of temperature is based on the Celsius scale.
The SI unit of heat is the joule.
The pressure of a gas is inversely proportional to its volume if the temperature and quantity of gas are held constant.
Boyle’s law relates the pressure and volume of a gas at constant temperature.
The velocity of gas molecules increases with an increase in temperature.
Charles’s law states that the volume of a gas is directly proportional to its absolute temperature at constant pressure.
The density of an object is its mass per unit volume.
The density of an object will decrease if it is taken to a higher altitude.
The upthrust or buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object.
Pascal’s law states that a change in pressure applied to an enclosed fluid is transmitted undiminished to all portions of the fluid.
Archimedes’ principle states that the buoyant force acting on an object submerged in a fluid is equal to the weight of the object displaced by the fluid.
Heat is the energy transferred between two objects due to a temperature difference.
The transfer of heat through a substance by the movement of the substance itself is called convection.
The transfer of heat through a substance without any movement of the substance is called conduction.
The transfer of heat through electromagnetic waves is called radiation.
The process of a liquid changing into a gas at its boiling point throughout the liquid is called boiling.
The process of a liquid changing into a gas at its surface, even below the boiling point, is called evaporation.
The change of a substance from a solid to a liquid is called melting.
The change of a substance from a gas directly to a solid without passing through the liquid state is called deposition.
The transfer of energy that occurs when molecules collide is called conduction.
Heat energy flows from an object with a higher temperature to an object with a lower temperature.
The transfer of heat through a vacuum by electromagnetic waves is radiation.
A bimetallic strip is used in thermostats because of the different rates of expansion of the two metals.
When the volume of a gas is doubled at constant temperature, the pressure becomes half of the initial pressure.
The state of matter with the least kinetic energy and weakest forces between particles is a gas
