Question 1
An electron moving towards the east enters a magnetic field directed towards the north. The force on the electron will be directed.
A) vertically upward
B) vertically downward
C) towards the west
D) towards the south.
Question 2.
In a LCR series circuit, at resonant frequency
A) the impedance and the current are maximum
B) the impedance is maximum
C) the current and voltage are out of phase
D) the current is maximum
Question 3:
The saturation current I of a photocell varies with distance from the source (d) is
A) I ∞ d
B) I ∞ d2
C) I ∞ I/d
D) I ∞ I/d2
Question 4:
A radioactive element X with half life 2 hrs decays giving a stable element Y. After a time t,ratio of X to Y atoms is 1:16 time t is
A) 6 hrs
B) 4 hrs
C) 8 hrs
D) 16 hrs
Question 5:
If no external voltage is applied across p-n junction, there would be
A) no electric field pointing across the junction .
B) an electric field pointing from n- type to p- type side across the junction.
C) an electric field pointing from p- type to n- type side across the junction.
D) a temporary electric field during formation of p-n junction that would subsequently disappear.