Physics Past Questions and Answers

Question 4881:

A cell with an emf of $1.5V$ and an internal resistance of $10.$. fohims 1 connegted to two resistances of $2.0$ and $3.0$ ohms in series. The current produced by this cell is

A. $0.25A$
B. $2.5A$
C. $0.5A$
D. $0.75A$

Question 4882:

Which of the following is not essential for the productipn of elèctron by thermionic emission?

A. Tungsten target
B. Reflection plate
c) Futrescent
C. Hot cathode

Question 4883:

If an object moves with a constant speed round a circlf, it has an acceleration which is

A. Constant in magnitude and varying $z$ cheation
B. Varying in magnitude and constant in pirection
C. Constant in magnitude andidireevion
D. Varying in magnitude and direction

Question 4884:

An electric string of length $X$ is stretched through a length by force F. The area of cross-section of the string is $A$ and its young modulus is $E$.
Which of the following expression is correct?

A. $F=\frac{EAc}{x}$
B. $F=\frac{EAe}{X^2}$
C. $F=\frac{EA{\epsilon }^2}{x}$
D. $F=\frac{EA{e}^2}{X^2}$

Question 4885:

The density of a solid is $130gcm3$ at the temperature of ${25}^{\circ }C$. Find the density at ${150}^{\circ }C$ the linear expansion of the solid is $2.0\times 105K1$.

A. $21.90gcm3$
B. $9.021.90gcm3$
C. $12.9gcm3$
D. $20.521.90gcm3$