Try increasing the resistivity of the resistor, rho. How does this change the "look" of the resistor? Describe how that relates to the formula you just write (direct, indirect etc.) What happens to the value of the resistance? Is this something that can be changed in a resistor that you would buy in a store to use in a circuit?

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.