Nuclei — Physics STD 12 Science — Question

Assertion :  The colour of the green flower seen through red glass appears to be dark.

Reason    : Red glass transmits only red light.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

Magnitude of produced magnetic field at any point inside a solenoid depends on:

Mark the correct options:

1. A diode valve can be used as a rectifier.
2. A triode valve can be used as a rectifier.
3. A diode valve can be used as an amplifier.
4. A triode valve can be used as an amplifier.

The current from the battery in circuit diagram shown is

(a) 1 A

(b) 2 A

(c) 1.5 A

(d) 3 A

A capacitor 4 μF charged to 50  V is connected to another capacitor of 2 μF  charged to 100 V with plates of like charges connected together. The total energy before and after connection in multiples of  (  is

(a) 1.5 and 1.33

(b) 1.33 and 1.5

(c) 3.0 and 2.67

(d) 2.67 and 3.0

Which experiment seemed to make it clear that light propogates as a wave?

In an electric heater 4 amp current passes for 1 minute at potential difference of 250 volt, the power of heater and energy consumed will be respectively

(a) 1 kW, 60 kJ

(b) 0.5 kW, 30 kJ

(c) 10 kW, 600 kJ

(d) None of these

Which of the following relations is correct ?

The capacity of a parallel plate condenser is C. Its capacity when the separation between the plates is halved will be

(a) 4 C

(b) 2C

(c)

(d)

Sixty-four drops are jointed together to form a bigger drop. If each small drop has a capacitance C, a potential V, and a charge q, then the capacitance of the bigger drop will be

(a) C

(b) 4C

(c) 16C

(d) 64C