Science Class 7th

451. The earth pin on plug is ____ than the live and neutral pins, so that it can’t be inserted in live or neutral hole of socket by mistake.

A) Longer

B) Thicker

C) Smaller

D) None

452. Fuse is present in?

A) Three pin plugs

B) Bulb

C) None

453. Which is much more sensitive to current?

A) MCB

B) Fuse

C) None

454. The main purpose of ___ is to prevent injury to humans and animals due to electric shock.

A) MCB

B) ELCB

C) Fuse

455.____ act like electrical circuit in our body.

A) Nerves

B) Blood

C) Oxygen

D) None

456. Humans are good conductors of electricity because of large amount of?

A) Nerves

B) Water

C) Veins

D) Heart

457. A fuse is used to:

A) Prevent electrical flow

B) Save electrical energy

C) Prevent excessive current

D) Increase voltage

458. Sun is a ?

A) Planet

B) Star

C) Comet

D) None

459. The clusters of billions of stars is called?

A) Andromeda

B) Galaxy

C) Universe

460. According to Scientists, most of the universe is?

A) Empty space

B) Full space

C) Filled space

D) None

461. ____ are the building blocks of the universe.

A) Galaxies

B) Stars

C) Moon

D) None

462. Big Bang theory is about?

A) Motion

B) Stars

C) Beginning of Universe

D) None

463. Big Bang theory explains formation of?

A) Planets

B) Stars

C) Galaxies

D) All of these

464. Galaxies are _______ from each other at a great speed in all directions.

A) Moving away

B) Fading away

C) Moving towards

D) None

465. “All the matter in universe was concentrated in ____ micrometer.

A) 2

B) 1

C) 4

D) 5

466. About billions years ago, super dense and hot atom exploded with a big bang.

A) 15

B) 16

C) 20

D) 22

467. Big Bang theory was proposed by?

A) Edwin Hubble

B) Newton

C) Einstein

468. Objects in space that emit light are?

A) Sun

B) Stars

C) Nebulae

D) All of these

469. Objects in space that reflect light?

A) Moon

B) Comets

C) Asteroids

D) All of these

470. Each second 600, 000, 000 tonnes of Hydrogen is converted to ___ in sun.

A) Neon

B) Argon

C) Helium

D) None