Specific Heat Capacities of Gases — Physics STD 12 Science — Question

The half-life of  is 5 days. What time is taken by (7/8)^th part of the sample to decay

(a) 3.4 days

(b) 10 days

(c) 15 days

(d) 20 days

In the following circuit a 10 m long potentiometer wire with resistance 1.2 ohm/m, a resistance R₁ and an accumulator of emf 2 V are connected in series. When the emf of thermocouple is 2.4 mV then the deflection in galvanometer is zero. The current supplied by the accumulator will be

(a) 4 × 10–4 A

(b) 8 × 10–4 A

(c) 4 × 10–3 A

(d) 8 × 10–3 A

A charged particle enters into a uniform magnetic field the parameter that remains constant is:

An infinitely long cylinder is kept parallel to an uniform magnetic field B directed along positive z axis. The direction of induced current as seen from the z axis will be

(a)  Clockwise of the +ve z axis	(b) Anticlockwise of the +ve z axis
(c) Zero	(d) Along the magnetic field

The filament of an electric bulb is made of:

If we increase the driving frequency in a circuit with a purely resistive load, then amplitude VR​.

Two batteries, one of emf 18 volts and internal resistance 2Ω and the other of emf 12 volt and internal resistance 1 Ω, are connected as shown. The voltmeter V will record a reading of

(a) 15 volt

(b) 30 volt

(c) 14 volt

(d) 18 volt

The combination of ‘NAND’ gates shown here under (figure) are equivalent to

(a) An OR gate and an AND gate respectively

(b) An AND gate and a NOT gate respectively

(c) An AND gate and an OR gate respectively

(d) An OR gate and a NOT gate respectively.

A lens of power + 2 diopters is placed in contact with a lens of power – 1 diopoter.  The combination will behave like

(a) A divergent lens of focal length 50 cm

(b) A convergent lens of focal length 50 cm

(c) A convergent lens of focal length 100 cm

(d) A divergent lens of focal length 100 cm

Density of nucleus is about :